Updated mailgun plugin

12 files changed, 1382 insertions, 0 deletions

diff --git a/inc/mailgun/php-http/curl-client/.php_cs b/inc/mailgun/php-http/curl-client/.php_cs
new file mode 100644
index 0000000..febeee5
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/.php_cs
@@ -0,0 +1,9 @@
+<?php
+
+return Symfony\CS\Config\Config::create()
+    ->level(Symfony\CS\FixerInterface::PSR2_LEVEL)
+    ->fixers([])
+    ->finder(
+        Symfony\CS\Finder\DefaultFinder::create()->in(__DIR__ . '/src')
+    )
+;
diff --git a/inc/mailgun/php-http/curl-client/.styleci.yml b/inc/mailgun/php-http/curl-client/.styleci.yml
new file mode 100644
index 0000000..4d43c93
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/.styleci.yml
@@ -0,0 +1,4 @@
+preset: psr2
+finder:
+    path:
+        - "src"
diff --git a/inc/mailgun/php-http/curl-client/CHANGELOG.md b/inc/mailgun/php-http/curl-client/CHANGELOG.md
new file mode 100644
index 0000000..a3f52d1
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/CHANGELOG.md
@@ -0,0 +1,163 @@
+# Change Log
+
+## 1.7 - 2017-02-09
+
+### Changed
+
+- #30: Make sure we rewind streams
+
+## 1.6.2 - 2017-01-02
+
+### Fixed
+
+- #29: Request not using CURLOPT_POSTFIELDS have content-length set to 
+
+### Changed
+
+- Use binary mode to create response body stream.
+
+
+## 1.6.1 - 2016-11-11
+
+### Fixed
+
+- #27: ErrorPlugin and sendAsyncRequest() incompatibility
+
+
+## 1.6 - 2016-09-12
+
+### Changed
+
+- `Client::sendRequest` now throws `Http\Client\Exception\NetworkException` on network errors.
+- `\UnexpectedValueException` replaced with `Http\Client\Exception\RequestException` in
+  `Client::sendRequest` and `Client::sendAsyncRequest`
+
+
+## 1.5.1 - 2016-08-29
+
+### Fixed
+
+- #26: Combining CurlClient with StopwatchPlugin causes Promise onRejected handler to never be
+  invoked.
+
+
+## 1.5 - 2016-08-03
+
+### Changed
+
+- Request body can be send with any method except GET, HEAD and TRACE.
+- #25: Make discovery a hard dependency. 
+
+
+## 1.4.2 - 2016-06-14
+
+### Added
+
+- #23: "php-http/async-client-implementation" added to "provide" section.
+
+
+## 1.4.1 - 2016-05-30
+
+### Fixed
+
+- #22: Cannot create the client using `HttpClientDiscovery`.
+
+
+## 1.4 - 2016-03-30
+
+### Changed
+
+- #20: Minimize memory usage when reading large response body.
+
+
+## 1.3 - 2016-03-14
+
+### Fixed
+
+- #18: Invalid "Expect" header.
+
+### Removed
+
+- #13: Remove HeaderParser. 
+
+
+## 1.2 - 2016-03-09
+
+### Added
+
+- #16: Make sure discovery can find the curl client
+
+### Fixed
+
+- #15: "Out of memory" sending large files.
+
+
+## 1.1.0 - 2016-01-29
+
+### Changed
+
+- Switch to php-http/message 1.0.
+
+
+## 1.0.0 - 2016-01-28
+
+First stable release.
+
+
+## 0.7.0 - 2016-01-26
+
+### Changed
+
+- Migrate from `php-http/discovery` and `php-http/utils` to `php-http/message`.
+
+## 0.6.0 - 2016-01-12
+
+### Changed
+
+- Root namespace changed from `Http\Curl` to `Http\Client\Curl`.
+- Main client class name renamed from `CurlHttpClient` to `Client`. 
+- Minimum required [php-http/discovery](https://packagist.org/packages/php-http/discovery)
+  version changed to 0.5.
+
+
+## 0.5.0 - 2015-12-18
+
+### Changed
+
+- Compatibility with php-http/httplug 1.0 beta
+- Switch to php-http/discovery 0.4
+
+
+## 0.4.0 - 2015-12-16
+
+### Changed
+
+- Switch to php-http/message-factory 1.0
+
+
+## 0.3.1 - 2015-12-14
+
+### Changed
+
+- Requirements fixed.
+
+
+## 0.3.0 - 2015-11-24
+
+### Changed
+
+- Use cURL constants as options keys.
+
+
+## 0.2.0 - 2015-11-17
+
+### Added
+
+- HttpAsyncClient support.
+
+
+## 0.1.0 - 2015-11-11
+
+### Added
+
+- Initial release
diff --git a/inc/mailgun/php-http/curl-client/LICENSE b/inc/mailgun/php-http/curl-client/LICENSE
new file mode 100644
index 0000000..8e2c4a0
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2015 PHP HTTP Team <team@php-http.org>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/inc/mailgun/php-http/curl-client/README.md b/inc/mailgun/php-http/curl-client/README.md
new file mode 100644
index 0000000..fc60b7e
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/README.md
@@ -0,0 +1,44 @@
+# Curl client for PHP HTTP
+
+[![Latest Version](https://img.shields.io/github/release/php-http/curl-client.svg?style=flat-square)](https://github.com/php-http/curl-client/releases)
+[![Software License](https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat-square)](LICENSE)
+[![Build Status](https://img.shields.io/travis/php-http/curl-client.svg?style=flat-square)](https://travis-ci.org/php-http/curl-client)
+[![Code Coverage](https://img.shields.io/scrutinizer/coverage/g/php-http/curl-client.svg?style=flat-square)](https://scrutinizer-ci.com/g/php-http/curl-client)
+[![Quality Score](https://img.shields.io/scrutinizer/g/php-http/curl-client.svg?style=flat-square)](https://scrutinizer-ci.com/g/php-http/curl-client)
+[![Total Downloads](https://img.shields.io/packagist/dt/php-http/curl-client.svg?style=flat-square)](https://packagist.org/packages/php-http/curl-client)
+
+The cURL client use the cURL PHP extension which must be activated in your `php.ini`.
+
+
+## Install
+
+Via Composer
+
+``` bash
+$ composer require php-http/curl-client
+```
+
+## Documentation
+
+Please see the [official documentation](http://docs.php-http.org/en/latest/clients/curl-client.html).
+
+## Testing
+
+``` bash
+$ composer test
+```
+
+## Contributing
+
+Please see [CONTRIBUTING](CONTRIBUTING.md) and [CONDUCT](CONDUCT.md) for details.
+
+
+## Security
+
+If you discover any security related issues, please contact us at
+[security@php-http.org](mailto:security@php-http.org).
+
+
+## License
+
+The MIT License (MIT). Please see [License File](LICENSE) for more information.
diff --git a/inc/mailgun/php-http/curl-client/composer.json b/inc/mailgun/php-http/curl-client/composer.json
new file mode 100644
index 0000000..5d16222
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/composer.json
@@ -0,0 +1,50 @@
+{
+    "name": "php-http/curl-client",
+    "description": "cURL client for PHP-HTTP",
+    "license": "MIT",
+    "keywords": ["http", "curl"],
+    "homepage": "http://php-http.org",
+    "authors": [
+        {
+            "name": "Михаил Красильников",
+            "email": "m.krasilnikov@yandex.ru"
+        }
+    ],
+    "prefer-stable": true,
+    "minimum-stability": "beta",
+    "config": {
+        "bin-dir": "vendor/bin"
+    },
+    "require": {
+        "php": "^5.5 || ^7.0",
+        "ext-curl": "*",
+        "php-http/httplug": "^1.0",
+        "php-http/message-factory": "^1.0.2",
+        "php-http/message": "^1.2",
+        "php-http/discovery": "^1.0"
+    },
+    "require-dev": {
+        "guzzlehttp/psr7": "^1.0",
+        "php-http/client-integration-tests": "^0.5.1",
+        "phpunit/phpunit": "^4.8.27",
+        "zendframework/zend-diactoros": "^1.0"
+    },
+    "autoload": {
+        "psr-4": {
+            "Http\\Client\\Curl\\": "src/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "Http\\Client\\Curl\\Tests\\": "tests/"
+        }
+    },
+    "provide": {
+        "php-http/client-implementation": "1.0",
+        "php-http/async-client-implementation": "1.0"
+    },
+    "scripts": {
+        "test": "vendor/bin/phpunit",
+        "test-ci": "vendor/bin/phpunit --coverage-clover build/coverage.xml"
+    }
+}
diff --git a/inc/mailgun/php-http/curl-client/puli.json b/inc/mailgun/php-http/curl-client/puli.json
new file mode 100644
index 0000000..b35768d
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/puli.json
@@ -0,0 +1,242 @@
+{
+    "version": "1.0",
+    "name": "php-http/curl-client",
+    "bindings": {
+        "98239b8b-103b-4f47-94c7-4cba49a05a1f": {
+            "_class": "Puli\\Discovery\\Binding\\ClassBinding",
+            "class": "Http\\Client\\Curl\\Client",
+            "type": "Http\\Client\\HttpAsyncClient"
+        },
+        "a6a79968-2aa5-427c-bbe1-a581d9a48321": {
+            "_class": "Puli\\Discovery\\Binding\\ClassBinding",
+            "class": "Http\\Client\\Curl\\Client",
+            "type": "Http\\Client\\HttpClient"
+        }
+    },
+    "config": {
+        "bootstrap-file": "vendor/autoload.php"
+    },
+    "packages": {
+        "clue/stream-filter": {
+            "install-path": "vendor/clue/stream-filter",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "doctrine/instantiator": {
+            "install-path": "vendor/doctrine/instantiator",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "guzzlehttp/psr7": {
+            "install-path": "vendor/guzzlehttp/psr7",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "justinrainbow/json-schema": {
+            "install-path": "vendor/justinrainbow/json-schema",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "paragonie/random_compat": {
+            "install-path": "vendor/paragonie/random_compat",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "php-http/adapter-integration-tests": {
+            "install-path": "vendor/php-http/adapter-integration-tests",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "php-http/discovery": {
+            "install-path": "vendor/php-http/discovery",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "php-http/httplug": {
+            "install-path": "vendor/php-http/httplug",
+            "installer": "composer"
+        },
+        "php-http/message": {
+            "install-path": "vendor/php-http/message",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "php-http/message-factory": {
+            "install-path": "vendor/php-http/message-factory",
+            "installer": "composer"
+        },
+        "php-http/promise": {
+            "install-path": "vendor/php-http/promise",
+            "installer": "composer"
+        },
+        "phpdocumentor/reflection-docblock": {
+            "install-path": "vendor/phpdocumentor/reflection-docblock",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "phpspec/prophecy": {
+            "install-path": "vendor/phpspec/prophecy",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "phpunit/php-code-coverage": {
+            "install-path": "vendor/phpunit/php-code-coverage",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "phpunit/php-file-iterator": {
+            "install-path": "vendor/phpunit/php-file-iterator",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "phpunit/php-text-template": {
+            "install-path": "vendor/phpunit/php-text-template",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "phpunit/php-timer": {
+            "install-path": "vendor/phpunit/php-timer",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "phpunit/php-token-stream": {
+            "install-path": "vendor/phpunit/php-token-stream",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "phpunit/phpunit": {
+            "install-path": "vendor/phpunit/phpunit",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "phpunit/phpunit-mock-objects": {
+            "install-path": "vendor/phpunit/phpunit-mock-objects",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "psr/http-message": {
+            "install-path": "vendor/psr/http-message",
+            "installer": "composer"
+        },
+        "psr/log": {
+            "install-path": "vendor/psr/log",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "puli/composer-plugin": {
+            "install-path": "vendor/puli/composer-plugin",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "puli/discovery": {
+            "install-path": "vendor/puli/discovery",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "puli/repository": {
+            "install-path": "vendor/puli/repository",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "puli/url-generator": {
+            "install-path": "vendor/puli/url-generator",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "ramsey/uuid": {
+            "install-path": "vendor/ramsey/uuid",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "sebastian/comparator": {
+            "install-path": "vendor/sebastian/comparator",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "sebastian/diff": {
+            "install-path": "vendor/sebastian/diff",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "sebastian/environment": {
+            "install-path": "vendor/sebastian/environment",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "sebastian/exporter": {
+            "install-path": "vendor/sebastian/exporter",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "sebastian/global-state": {
+            "install-path": "vendor/sebastian/global-state",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "sebastian/recursion-context": {
+            "install-path": "vendor/sebastian/recursion-context",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "sebastian/version": {
+            "install-path": "vendor/sebastian/version",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "seld/jsonlint": {
+            "install-path": "vendor/seld/jsonlint",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "symfony/filesystem": {
+            "install-path": "vendor/symfony/filesystem",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "symfony/process": {
+            "install-path": "vendor/symfony/process",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "symfony/yaml": {
+            "install-path": "vendor/symfony/yaml",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "th3n3rd/cartesian-product": {
+            "install-path": "vendor/th3n3rd/cartesian-product",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "webmozart/assert": {
+            "install-path": "vendor/webmozart/assert",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "webmozart/expression": {
+            "install-path": "vendor/webmozart/expression",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "webmozart/glob": {
+            "install-path": "vendor/webmozart/glob",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "webmozart/json": {
+            "install-path": "vendor/webmozart/json",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "webmozart/path-util": {
+            "install-path": "vendor/webmozart/path-util",
+            "installer": "composer",
+            "env": "dev"
+        },
+        "zendframework/zend-diactoros": {
+            "install-path": "vendor/zendframework/zend-diactoros",
+            "installer": "composer",
+            "env": "dev"
+        }
+    }
+}
diff --git a/inc/mailgun/php-http/curl-client/src/Client.php b/inc/mailgun/php-http/curl-client/src/Client.php
new file mode 100644
index 0000000..5696ab3
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/src/Client.php
@@ -0,0 +1,371 @@
+<?php
+namespace Http\Client\Curl;
+
+use Http\Client\Exception;
+use Http\Client\HttpAsyncClient;
+use Http\Client\HttpClient;
+use Http\Discovery\MessageFactoryDiscovery;
+use Http\Discovery\StreamFactoryDiscovery;
+use Http\Message\MessageFactory;
+use Http\Message\StreamFactory;
+use Http\Promise\Promise;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+/**
+ * PSR-7 compatible cURL based HTTP client
+ *
+ * @license http://opensource.org/licenses/MIT MIT
+ *
+ * @author  Михаил Красильников <m.krasilnikov@yandex.ru>
+ * @author  Blake Williams <github@shabbyrobe.org>
+ *
+ * @api
+ * @since   1.0
+ */
+class Client implements HttpClient, HttpAsyncClient
+{
+    /**
+     * cURL options
+     *
+     * @var array
+     */
+    private $options;
+
+    /**
+     * PSR-7 message factory
+     *
+     * @var MessageFactory
+     */
+    private $messageFactory;
+
+    /**
+     * PSR-7 stream factory
+     *
+     * @var StreamFactory
+     */
+    private $streamFactory;
+
+    /**
+     * cURL synchronous requests handle
+     *
+     * @var resource|null
+     */
+    private $handle = null;
+
+    /**
+     * Simultaneous requests runner
+     *
+     * @var MultiRunner|null
+     */
+    private $multiRunner = null;
+
+    /**
+     * Create new client
+     *
+     * @param MessageFactory|null $messageFactory HTTP Message factory
+     * @param StreamFactory|null  $streamFactory  HTTP Stream factory
+     * @param array               $options        cURL options (see http://php.net/curl_setopt)
+     *
+     * @throws \Http\Discovery\Exception\NotFoundException If factory discovery failed.
+     *
+     * @since 1.0
+     */
+    public function __construct(
+        MessageFactory $messageFactory = null,
+        StreamFactory $streamFactory = null,
+        array $options = []
+    ) {
+        $this->messageFactory = $messageFactory ?: MessageFactoryDiscovery::find();
+        $this->streamFactory = $streamFactory ?: StreamFactoryDiscovery::find();
+        $this->options = $options;
+    }
+
+    /**
+     * Release resources if still active
+     */
+    public function __destruct()
+    {
+        if (is_resource($this->handle)) {
+            curl_close($this->handle);
+        }
+    }
+
+    /**
+     * Sends a PSR-7 request.
+     *
+     * @param RequestInterface $request
+     *
+     * @return ResponseInterface
+     *
+     * @throws \Http\Client\Exception\NetworkException In case of network problems.
+     * @throws \Http\Client\Exception\RequestException On invalid request.
+     * @throws \InvalidArgumentException For invalid header names or values.
+     * @throws \RuntimeException         If creating the body stream fails.
+     *
+     * @since 1.6 \UnexpectedValueException replaced with RequestException.
+     * @since 1.6 Throw NetworkException on network errors.
+     * @since 1.0
+     */
+    public function sendRequest(RequestInterface $request)
+    {
+        $responseBuilder = $this->createResponseBuilder();
+        $options = $this->createCurlOptions($request, $responseBuilder);
+
+        if (is_resource($this->handle)) {
+            curl_reset($this->handle);
+        } else {
+            $this->handle = curl_init();
+        }
+
+        curl_setopt_array($this->handle, $options);
+        curl_exec($this->handle);
+
+        $errno = curl_errno($this->handle);
+        switch ($errno) {
+            case CURLE_OK:
+                // All OK, no actions needed.
+                break;
+            case CURLE_COULDNT_RESOLVE_PROXY:
+            case CURLE_COULDNT_RESOLVE_HOST:
+            case CURLE_COULDNT_CONNECT:
+            case CURLE_OPERATION_TIMEOUTED:
+            case CURLE_SSL_CONNECT_ERROR:
+                throw new Exception\NetworkException(curl_error($this->handle), $request);
+            default:
+                throw new Exception\RequestException(curl_error($this->handle), $request);
+        }
+
+        $response = $responseBuilder->getResponse();
+        $response->getBody()->seek(0);
+
+        return $response;
+    }
+
+    /**
+     * Sends a PSR-7 request in an asynchronous way.
+     *
+     * @param RequestInterface $request
+     *
+     * @return Promise
+     *
+     * @throws \Http\Client\Exception\RequestException On invalid request.
+     * @throws \InvalidArgumentException For invalid header names or values.
+     * @throws \RuntimeException If creating the body stream fails.
+     *
+     * @since 1.6 \UnexpectedValueException replaced with RequestException.
+     * @since 1.0
+     */
+    public function sendAsyncRequest(RequestInterface $request)
+    {
+        if (!$this->multiRunner instanceof MultiRunner) {
+            $this->multiRunner = new MultiRunner();
+        }
+
+        $handle = curl_init();
+        $responseBuilder = $this->createResponseBuilder();
+        $options = $this->createCurlOptions($request, $responseBuilder);
+        curl_setopt_array($handle, $options);
+
+        $core = new PromiseCore($request, $handle, $responseBuilder);
+        $promise = new CurlPromise($core, $this->multiRunner);
+        $this->multiRunner->add($core);
+
+        return $promise;
+    }
+
+    /**
+     * Generates cURL options
+     *
+     * @param RequestInterface $request
+     * @param ResponseBuilder  $responseBuilder
+     *
+     * @throws \Http\Client\Exception\RequestException On invalid request.
+     * @throws \InvalidArgumentException For invalid header names or values.
+     * @throws \RuntimeException if can not read body
+     *
+     * @return array
+     */
+    private function createCurlOptions(RequestInterface $request, ResponseBuilder $responseBuilder)
+    {
+        $options = $this->options;
+
+        $options[CURLOPT_HEADER] = false;
+        $options[CURLOPT_RETURNTRANSFER] = false;
+        $options[CURLOPT_FOLLOWLOCATION] = false;
+
+        try {
+            $options[CURLOPT_HTTP_VERSION]
+                = $this->getProtocolVersion($request->getProtocolVersion());
+        } catch (\UnexpectedValueException $e) {
+            throw new Exception\RequestException($e->getMessage(), $request);
+        }
+        $options[CURLOPT_URL] = (string) $request->getUri();
+
+        $options = $this->addRequestBodyOptions($request, $options);
+
+        $options[CURLOPT_HTTPHEADER] = $this->createHeaders($request, $options);
+
+        if ($request->getUri()->getUserInfo()) {
+            $options[CURLOPT_USERPWD] = $request->getUri()->getUserInfo();
+        }
+
+        $options[CURLOPT_HEADERFUNCTION] = function ($ch, $data) use ($responseBuilder) {
+            $str = trim($data);
+            if ('' !== $str) {
+                if (strpos(strtolower($str), 'http/') === 0) {
+                    $responseBuilder->setStatus($str)->getResponse();
+                } else {
+                    $responseBuilder->addHeader($str);
+                }
+            }
+
+            return strlen($data);
+        };
+
+        $options[CURLOPT_WRITEFUNCTION] = function ($ch, $data) use ($responseBuilder) {
+            return $responseBuilder->getResponse()->getBody()->write($data);
+        };
+
+        return $options;
+    }
+
+    /**
+     * Return cURL constant for specified HTTP version
+     *
+     * @param string $requestVersion
+     *
+     * @throws \UnexpectedValueException if unsupported version requested
+     *
+     * @return int
+     */
+    private function getProtocolVersion($requestVersion)
+    {
+        switch ($requestVersion) {
+            case '1.0':
+                return CURL_HTTP_VERSION_1_0;
+            case '1.1':
+                return CURL_HTTP_VERSION_1_1;
+            case '2.0':
+                if (defined('CURL_HTTP_VERSION_2_0')) {
+                    return CURL_HTTP_VERSION_2_0;
+                }
+                throw new \UnexpectedValueException('libcurl 7.33 needed for HTTP 2.0 support');
+        }
+
+        return CURL_HTTP_VERSION_NONE;
+    }
+
+    /**
+     * Add request body related cURL options.
+     *
+     * @param RequestInterface $request
+     * @param array            $options
+     *
+     * @return array
+     */
+    private function addRequestBodyOptions(RequestInterface $request, array $options)
+    {
+        /*
+         * Some HTTP methods cannot have payload:
+         *
+         * - GET — cURL will automatically change method to PUT or POST if we set CURLOPT_UPLOAD or
+         *   CURLOPT_POSTFIELDS.
+         * - HEAD — cURL treats HEAD as GET request with a same restrictions.
+         * - TRACE — According to RFC7231: a client MUST NOT send a message body in a TRACE request.
+         */
+        if (!in_array($request->getMethod(), ['GET', 'HEAD', 'TRACE'], true)) {
+            $body = $request->getBody();
+            $bodySize = $body->getSize();
+            if ($bodySize !== 0) {
+                if ($body->isSeekable()) {
+                    $body->rewind();
+                }
+
+                // Message has non empty body.
+                if (null === $bodySize || $bodySize > 1024 * 1024) {
+                    // Avoid full loading large or unknown size body into memory
+                    $options[CURLOPT_UPLOAD] = true;
+                    if (null !== $bodySize) {
+                        $options[CURLOPT_INFILESIZE] = $bodySize;
+                    }
+                    $options[CURLOPT_READFUNCTION] = function ($ch, $fd, $length) use ($body) {
+                        return $body->read($length);
+                    };
+                } else {
+                    // Small body can be loaded into memory
+                    $options[CURLOPT_POSTFIELDS] = (string) $body;
+                }
+            }
+        }
+
+        if ($request->getMethod() === 'HEAD') {
+            // This will set HTTP method to "HEAD".
+            $options[CURLOPT_NOBODY] = true;
+        } elseif ($request->getMethod() !== 'GET') {
+            // GET is a default method. Other methods should be specified explicitly.
+            $options[CURLOPT_CUSTOMREQUEST] = $request->getMethod();
+        }
+
+        return $options;
+    }
+
+    /**
+     * Create headers array for CURLOPT_HTTPHEADER
+     *
+     * @param RequestInterface $request
+     * @param array            $options cURL options
+     *
+     * @return string[]
+     */
+    private function createHeaders(RequestInterface $request, array $options)
+    {
+        $curlHeaders = [];
+        $headers = $request->getHeaders();
+        foreach ($headers as $name => $values) {
+            $header = strtolower($name);
+            if ('expect' === $header) {
+                // curl-client does not support "Expect-Continue", so dropping "expect" headers
+                continue;
+            }
+            if ('content-length' === $header) {
+                if (array_key_exists(CURLOPT_POSTFIELDS, $options)) {
+                    // Small body content length can be calculated here.
+                    $values = [strlen($options[CURLOPT_POSTFIELDS])];
+                } elseif (!array_key_exists(CURLOPT_READFUNCTION, $options)) {
+                    // Else if there is no body, forcing "Content-length" to 0
+                    $values = [0];
+                }
+            }
+            foreach ($values as $value) {
+                $curlHeaders[] = $name . ': ' . $value;
+            }
+        }
+        /*
+         * curl-client does not support "Expect-Continue", but cURL adds "Expect" header by default.
+         * We can not suppress it, but we can set it to empty.
+         */
+        $curlHeaders[] = 'Expect:';
+
+        return $curlHeaders;
+    }
+
+    /**
+     * Create new ResponseBuilder instance
+     *
+     * @return ResponseBuilder
+     *
+     * @throws \RuntimeException If creating the stream from $body fails.
+     */
+    private function createResponseBuilder()
+    {
+        try {
+            $body = $this->streamFactory->createStream(fopen('php://temp', 'w+b'));
+        } catch (\InvalidArgumentException $e) {
+            throw new \RuntimeException('Can not create "php://temp" stream.');
+        }
+        $response = $this->messageFactory->createResponse(200, null, [], $body);
+
+        return new ResponseBuilder($response);
+    }
+}
diff --git a/inc/mailgun/php-http/curl-client/src/CurlPromise.php b/inc/mailgun/php-http/curl-client/src/CurlPromise.php
new file mode 100644
index 0000000..68a775c
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/src/CurlPromise.php
@@ -0,0 +1,108 @@
+<?php
+namespace Http\Client\Curl;
+
+use Http\Promise\Promise;
+
+/**
+ * Promise represents a response that may not be available yet, but will be resolved at some point
+ * in future. It acts like a proxy to the actual response.
+ *
+ * This interface is an extension of the promises/a+ specification https://promisesaplus.com/
+ * Value is replaced by an object where its class implement a Psr\Http\Message\RequestInterface.
+ * Reason is replaced by an object where its class implement a Http\Client\Exception.
+ *
+ * @license http://opensource.org/licenses/MIT MIT
+ *
+ * @author  Михаил Красильников <m.krasilnikov@yandex.ru>
+ */
+class CurlPromise implements Promise
+{
+    /**
+     * Shared promise core
+     *
+     * @var PromiseCore
+     */
+    private $core;
+
+    /**
+     * Requests runner
+     *
+     * @var MultiRunner
+     */
+    private $runner;
+
+    /**
+     * Create new promise.
+     *
+     * @param PromiseCore $core   Shared promise core
+     * @param MultiRunner $runner Simultaneous requests runner
+     */
+    public function __construct(PromiseCore $core, MultiRunner $runner)
+    {
+        $this->core = $core;
+        $this->runner = $runner;
+    }
+
+    /**
+     * Add behavior for when the promise is resolved or rejected.
+     *
+     * If you do not care about one of the cases, you can set the corresponding callable to null
+     * The callback will be called when the response or exception arrived and never more than once.
+     *
+     * @param callable $onFulfilled Called when a response will be available.
+     * @param callable $onRejected  Called when an error happens.
+     *
+     * You must always return the Response in the interface or throw an Exception.
+     *
+     * @return Promise Always returns a new promise which is resolved with value of the executed
+     *                 callback (onFulfilled / onRejected).
+     */
+    public function then(callable $onFulfilled = null, callable $onRejected = null)
+    {
+        if ($onFulfilled) {
+            $this->core->addOnFulfilled($onFulfilled);
+        }
+        if ($onRejected) {
+            $this->core->addOnRejected($onRejected);
+        }
+
+        return new self($this->core, $this->runner);
+    }
+
+    /**
+     * Get the state of the promise, one of PENDING, FULFILLED or REJECTED.
+     *
+     * @return string
+     */
+    public function getState()
+    {
+        return $this->core->getState();
+    }
+
+    /**
+     * Wait for the promise to be fulfilled or rejected.
+     *
+     * When this method returns, the request has been resolved and the appropriate callable has terminated.
+     *
+     * When called with the unwrap option
+     *
+     * @param bool $unwrap Whether to return resolved value / throw reason or not
+     *
+     * @return \Psr\Http\Message\ResponseInterface|null Resolved value, null if $unwrap is set to false
+     *
+     * @throws \Http\Client\Exception The rejection reason.
+     */
+    public function wait($unwrap = true)
+    {
+        $this->runner->wait($this->core);
+
+        if ($unwrap) {
+            if ($this->core->getState() === self::REJECTED) {
+                throw $this->core->getException();
+            }
+
+            return $this->core->getResponse();
+        }
+        return null;
+    }
+}
diff --git a/inc/mailgun/php-http/curl-client/src/MultiRunner.php b/inc/mailgun/php-http/curl-client/src/MultiRunner.php
new file mode 100644
index 0000000..9094c0f
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/src/MultiRunner.php
@@ -0,0 +1,127 @@
+<?php
+namespace Http\Client\Curl;
+
+use Http\Client\Exception\RequestException;
+
+/**
+ * Simultaneous requests runner
+ *
+ * @license http://opensource.org/licenses/MIT MIT
+ *
+ * @author  Михаил Красильников <m.krasilnikov@yandex.ru>
+ */
+class MultiRunner
+{
+    /**
+     * cURL multi handle
+     *
+     * @var resource|null
+     */
+    private $multiHandle = null;
+
+    /**
+     * Awaiting cores
+     *
+     * @var PromiseCore[]
+     */
+    private $cores = [];
+
+    /**
+     * Release resources if still active
+     */
+    public function __destruct()
+    {
+        if (is_resource($this->multiHandle)) {
+            curl_multi_close($this->multiHandle);
+        }
+    }
+
+    /**
+     * Add promise to runner
+     *
+     * @param PromiseCore $core
+     */
+    public function add(PromiseCore $core)
+    {
+        foreach ($this->cores as $existed) {
+            if ($existed === $core) {
+                return;
+            }
+        }
+
+        $this->cores[] = $core;
+
+        if (null === $this->multiHandle) {
+            $this->multiHandle = curl_multi_init();
+        }
+        curl_multi_add_handle($this->multiHandle, $core->getHandle());
+    }
+
+    /**
+     * Remove promise from runner
+     *
+     * @param PromiseCore $core
+     */
+    public function remove(PromiseCore $core)
+    {
+        foreach ($this->cores as $index => $existed) {
+            if ($existed === $core) {
+                curl_multi_remove_handle($this->multiHandle, $core->getHandle());
+                unset($this->cores[$index]);
+                return;
+            }
+        }
+    }
+
+    /**
+     * Wait for request(s) to be completed.
+     *
+     * @param PromiseCore|null $targetCore
+     */
+    public function wait(PromiseCore $targetCore = null)
+    {
+        do {
+            $status = curl_multi_exec($this->multiHandle, $active);
+            $info = curl_multi_info_read($this->multiHandle);
+            if (false !== $info) {
+                $core = $this->findCoreByHandle($info['handle']);
+
+                if (null === $core) {
+                    // We have no promise for this handle. Drop it.
+                    curl_multi_remove_handle($this->multiHandle, $info['handle']);
+                    continue;
+                }
+
+                if (CURLE_OK === $info['result']) {
+                    $core->fulfill();
+                } else {
+                    $error = curl_error($core->getHandle());
+                    $core->reject(new RequestException($error, $core->getRequest()));
+                }
+                $this->remove($core);
+
+                // This is a promise we are waited for. So exiting wait().
+                if ($core === $targetCore) {
+                    return;
+                }
+            }
+        } while ($status === CURLM_CALL_MULTI_PERFORM || $active);
+    }
+
+    /**
+     * Find core by handle.
+     *
+     * @param resource $handle
+     *
+     * @return PromiseCore|null
+     */
+    private function findCoreByHandle($handle)
+    {
+        foreach ($this->cores as $core) {
+            if ($core->getHandle() === $handle) {
+                return $core;
+            }
+        }
+        return null;
+    }
+}
diff --git a/inc/mailgun/php-http/curl-client/src/PromiseCore.php b/inc/mailgun/php-http/curl-client/src/PromiseCore.php
new file mode 100644
index 0000000..f1a3aa5
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/src/PromiseCore.php
@@ -0,0 +1,224 @@
+<?php
+namespace Http\Client\Curl;
+
+use Http\Client\Exception;
+use Http\Promise\Promise;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+/**
+ * Shared promises core.
+ *
+ * @license http://opensource.org/licenses/MIT MIT
+ *
+ * @author  Михаил Красильников <m.krasilnikov@yandex.ru>
+ */
+class PromiseCore
+{
+    /**
+     * HTTP request
+     *
+     * @var RequestInterface
+     */
+    private $request;
+
+    /**
+     * cURL handle
+     *
+     * @var resource
+     */
+    private $handle;
+
+    /**
+     * Response builder
+     *
+     * @var ResponseBuilder
+     */
+    private $responseBuilder;
+
+    /**
+     * Promise state
+     *
+     * @var string
+     */
+    private $state;
+
+    /**
+     * Exception
+     *
+     * @var Exception|null
+     */
+    private $exception = null;
+
+    /**
+     * Functions to call when a response will be available.
+     *
+     * @var callable[]
+     */
+    private $onFulfilled = [];
+
+    /**
+     * Functions to call when an error happens.
+     *
+     * @var callable[]
+     */
+    private $onRejected = [];
+
+    /**
+     * Create shared core.
+     *
+     * @param RequestInterface $request HTTP request
+     * @param resource         $handle  cURL handle
+     * @param ResponseBuilder  $responseBuilder
+     */
+    public function __construct(
+        RequestInterface $request,
+        $handle,
+        ResponseBuilder $responseBuilder
+    ) {
+        assert('is_resource($handle)');
+        assert('get_resource_type($handle) === "curl"');
+
+        $this->request = $request;
+        $this->handle = $handle;
+        $this->responseBuilder = $responseBuilder;
+        $this->state = Promise::PENDING;
+    }
+
+    /**
+     * Add on fulfilled callback.
+     *
+     * @param callable $callback
+     */
+    public function addOnFulfilled(callable $callback)
+    {
+        if ($this->getState() === Promise::PENDING) {
+            $this->onFulfilled[] = $callback;
+        } elseif ($this->getState() === Promise::FULFILLED) {
+            $response = call_user_func($callback, $this->responseBuilder->getResponse());
+            if ($response instanceof ResponseInterface) {
+                $this->responseBuilder->setResponse($response);
+            }
+        }
+    }
+
+    /**
+     * Add on rejected callback.
+     *
+     * @param callable $callback
+     */
+    public function addOnRejected(callable $callback)
+    {
+        if ($this->getState() === Promise::PENDING) {
+            $this->onRejected[] = $callback;
+        } elseif ($this->getState() === Promise::REJECTED) {
+            $this->exception = call_user_func($callback, $this->exception);
+        }
+    }
+
+    /**
+     * Return cURL handle
+     *
+     * @return resource
+     */
+    public function getHandle()
+    {
+        return $this->handle;
+    }
+
+    /**
+     * Get the state of the promise, one of PENDING, FULFILLED or REJECTED.
+     *
+     * @return string
+     */
+    public function getState()
+    {
+        return $this->state;
+    }
+
+    /**
+     * Return request
+     *
+     * @return RequestInterface
+     */
+    public function getRequest()
+    {
+        return $this->request;
+    }
+
+    /**
+     * Return the value of the promise (fulfilled).
+     *
+     * @return ResponseInterface Response Object only when the Promise is fulfilled.
+     */
+    public function getResponse()
+    {
+        return $this->responseBuilder->getResponse();
+    }
+
+    /**
+     * Get the reason why the promise was rejected.
+     *
+     * If the exception is an instance of Http\Client\Exception\HttpException it will contain
+     * the response object with the status code and the http reason.
+     *
+     * @return Exception Exception Object only when the Promise is rejected.
+     *
+     * @throws \LogicException When the promise is not rejected.
+     */
+    public function getException()
+    {
+        if (null === $this->exception) {
+            throw new \LogicException('Promise is not rejected');
+        }
+
+        return $this->exception;
+    }
+
+    /**
+     * Fulfill promise.
+     */
+    public function fulfill()
+    {
+        $this->state = Promise::FULFILLED;
+        $response = $this->responseBuilder->getResponse();
+        try {
+            $response->getBody()->seek(0);
+        } catch (\RuntimeException $e) {
+            $exception = new Exception\TransferException($e->getMessage(), $e->getCode(), $e);
+            $this->reject($exception);
+
+            return;
+        }
+
+        while (count($this->onFulfilled) > 0) {
+            $callback = array_shift($this->onFulfilled);
+            $response = call_user_func($callback, $response);
+        }
+
+        if ($response instanceof ResponseInterface) {
+            $this->responseBuilder->setResponse($response);
+        }
+    }
+
+    /**
+     * Reject promise.
+     *
+     * @param Exception $exception Reject reason.
+     */
+    public function reject(Exception $exception)
+    {
+        $this->exception = $exception;
+        $this->state = Promise::REJECTED;
+
+        while (count($this->onRejected) > 0) {
+            $callback = array_shift($this->onRejected);
+            try {
+                $exception = call_user_func($callback, $this->exception);
+                $this->exception = $exception;
+            } catch (Exception $exception) {
+                $this->exception = $exception;
+            }
+        }
+    }
+}
diff --git a/inc/mailgun/php-http/curl-client/src/ResponseBuilder.php b/inc/mailgun/php-http/curl-client/src/ResponseBuilder.php
new file mode 100644
index 0000000..99e79db
--- /dev/null
+++ b/inc/mailgun/php-http/curl-client/src/ResponseBuilder.php
@@ -0,0 +1,21 @@
+<?php
+namespace Http\Client\Curl;
+
+use Http\Message\Builder\ResponseBuilder as OriginalResponseBuilder;
+use Psr\Http\Message\ResponseInterface;
+
+/**
+ * Extended response builder
+ */
+class ResponseBuilder extends OriginalResponseBuilder
+{
+    /**
+     * Replace response with a new instance
+     *
+     * @param ResponseInterface $response
+     */
+    public function setResponse(ResponseInterface $response)
+    {
+        $this->response = $response;
+    }
+}