Feature/connect cancel (#74)

* Implemented connection cancellation

* Made connect requests return immediately and created a separate connection complete notification

* Fix spelling

* Fix sorting

* Add separate lock for cancellation source map

test/Microsoft.SqlTools.ServiceLayer.Test/Utility/TestUtils.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Runtime.InteropServices;
+using System.Threading;
 
 namespace Microsoft.SqlTools.ServiceLayer.Test.Utility
 {
@@ -21,5 +22,23 @@ namespace Microsoft.SqlTools.ServiceLayer.Test.Utility
                 test();
             }
         }
+
+        /// <summary>
+        /// Wait for a condition to be true for a limited amount of time.
+        /// </summary>
+        /// <param name="condition">Function that returns a boolean on a condition</param>
+        /// <param name="intervalMilliseconds">Number of milliseconds to wait between test intervals.</param>
+        /// <param name="intervalCount">Number of test intervals to perform before giving up.</param>
+        /// <returns>True if the condition was met before the test interval limit.</returns>
+        public static bool WaitFor(Func<bool> condition, int intervalMilliseconds = 10, int intervalCount = 200)
+        {
+            int count = 0;
+            while (count++ < intervalCount && !condition.Invoke())
+            {
+                Thread.Sleep(intervalMilliseconds);
+            }
+
+            return (count < intervalCount);
+        }
     }
 }