Fix #567: Add proxy support for MultiCurl

examples/multi_curl_proxy_socks5.php

@@ -0,0 +1,16 @@
+<?php
+require __DIR__ . '/../vendor/autoload.php';
+
+use \Curl\MultiCurl;
+
+// If needed, start a SOCKS 5 proxy tunnel:
+//   $ ssh -D 8080 -C -N -v user@example.com
+
+$multi_curl = new MultiCurl();
+$multi_curl->setProxy('127.0.0.1:8080');
+$multi_curl->setProxyType(CURLPROXY_SOCKS5);
+$multi_curl->addGet('https://httpbin.org/ip');
+$multi_curl->complete(function ($instance) {
+    var_dump($instance->response);
+});
+$multi_curl->start();