Added multiplayer plugin

Assets/Mirror/Runtime/Transport/Telepathy/ThreadExtensions.cs

@@ -0,0 +1,26 @@
+using System.Threading;
+
+namespace Telepathy
+{
+    public static class ThreadExtensions
+    {
+        // helper function to abort a thread and not return until it's fully done
+        public static void AbortAndJoin(this Thread thread)
+        {
+            // kill thread at all costs
+            // -> calling .Join would sometimes wait forever
+            // -> calling .Interrupt only interrupts certain states.
+            // => Abort() is the better solution.
+            thread.Abort();
+
+            // wait until thread is TRULY finished. this is the only way
+            // to guarantee that everything was properly cleaned up before
+            // returning.
+            // => this means that this function may sometimes block for a while
+            //    but there is no other way to guarantee that everything is
+            //    cleaned up properly by the time Stop() returns.
+            //    we have to live with the wait time.
+            thread.Join();
+        }
+    }
+}