Add proxy support

Author: kenjiuno

PusherClient/Connection.cs

@@ -4,6 +4,7 @@
 using System.Threading.Tasks;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
+using SuperSocket.ClientEngine;
 //using Nito.AsyncEx;
 using WebSocket4Net;
 
@@ -16,6 +17,7 @@ internal class Connection
         private readonly string _url;
         private readonly IPusher _pusher;
         private bool _allowReconnect = true;
+        private Func<IProxyConnector> _proxyFactory;
 
         private int _backOffMillis;
 
@@ -31,10 +33,11 @@ internal class Connection
         private TaskCompletionSource<ConnectionState> _connectionTaskComplete = null;
         private TaskCompletionSource<ConnectionState> _disconnectionTaskComplete = null;
 
-        public Connection(IPusher pusher, string url)
+        public Connection(IPusher pusher, string url, Func<IProxyConnector> proxyFactory = null)
         {
             _pusher = pusher;
             _url = url;
+            _proxyFactory = proxyFactory;
         }
 
         internal Task<ConnectionState> Connect()
@@ -57,7 +60,8 @@ internal Task<ConnectionState> Connect()
             _websocket = new WebSocket(_url)
             {
                 EnableAutoSendPing = true,
-                AutoSendPingInterval = 1
+                AutoSendPingInterval = 1,
+                Proxy = _proxyFactory?.Invoke(),
             };
 
             _websocket.Opened += websocket_Opened;

PusherClient/Pusher.cs

@@ -196,7 +196,7 @@ public async Task<ConnectionState> ConnectAsync()
 
                 var url = ConstructUrl();
 
-                _connection = new Connection(this, url);
+                _connection = new Connection(this, url, Options.ProxyFactory);
                 connectionResult = await _connection.Connect();
             }
             finally

PusherClient/PusherOptions.cs

@@ -1,4 +1,7 @@
-namespace PusherClient
+using SuperSocket.ClientEngine;
+using System;
+
+namespace PusherClient
 {
     /// <summary>
     /// The Options to set up the connection with <see cref="Pusher"/>
@@ -20,6 +23,12 @@ public class PusherOptions
         /// </summary>
         public string Cluster { get; set; } = "mt1";
 
+        /// <summary>
+        /// Gets or set a IProxyConnector implementation instance may be one of
+        /// HttpConnectProxy, Socks4Connector, or Socks5Connector.
+        /// </summary>
+        public Func<IProxyConnector> ProxyFactory { get; set; }
+
         internal string Host => $"ws-{Cluster}.pusher.com";
     }
 }