Added NightAlert project for travel kit

ThirdParty/EngineIoClientDotNet/Src/EngineIoClientDotNet.mono/Thread/Heartbeat_net35.cs

@@ -0,0 +1,55 @@
+using System;
+using System.ComponentModel;
+using System.Threading;
+
+namespace Quobject.EngineIoClientDotNet.Thread
+{
+    public class Heartbeat
+    {
+        private volatile bool gotHeartbeat = false;
+        private BackgroundWorker heartBeatTimer;
+        private CancellationTokenSource ts;
+
+        private Heartbeat()
+        {
+            ts = new CancellationTokenSource();
+        }
+
+        public static Heartbeat Start(Action onTimeout, int timeout)
+        {
+            Heartbeat heartbeat = new Heartbeat();
+            heartbeat.Run(onTimeout, timeout);
+            return heartbeat;            
+        }
+
+        public void OnHeartbeat()
+        {
+            gotHeartbeat = true;
+        }
+
+        private void Run(Action onTimeout, int timeout)
+        {
+            heartBeatTimer = new BackgroundWorker();
+
+            heartBeatTimer.DoWork += (s, e) =>
+            {
+                while (!ts.IsCancellationRequested)
+                {
+                    System.Threading.Thread.Sleep(timeout);
+                    if (!gotHeartbeat && !ts.IsCancellationRequested)
+                    {
+                        onTimeout();
+                        break;
+                    }
+                }
+            };
+
+            heartBeatTimer.RunWorkerAsync();
+        }
+
+        public void Stop()
+        {
+            ts.Cancel();
+        }
+    }
+}