Change connection task error handling. (#873)

Author: scottf

Diff for: src/NATS.Client/Connection.cs

@@ -388,17 +388,24 @@ public virtual void open(Srv s, Options options)
                         client.Client.DualMode = true;
 
                     var task = client.ConnectAsync(s.Url.Host, s.Url.Port);
-                    // avoid raising TaskScheduler.UnobservedTaskException if the timeout occurs first
-                    task.ContinueWith(t =>
+                    NATSConnectionException nce = null;
+                    try
                     {
-                        GC.KeepAlive(t.Exception);
-                        close(client);
-                    }, TaskContinuationOptions.OnlyOnFaulted);
-                    if (!task.Wait(TimeSpan.FromMilliseconds(options.Timeout)))
+                        if (!task.Wait(TimeSpan.FromMilliseconds(options.Timeout)))
+                        {
+                            nce = new NATSConnectionException("timeout");
+                        }
+                    }
+                    catch (Exception e)
+                    {
+                        nce = new NATSConnectionException(e.Message);
+                    }
+
+                    if (nce != null)
                     {
                         close(client);
                         client = null;
-                        throw new NATSConnectionException("timeout");
+                        throw nce;
                     }
 
                     client.NoDelay = false;

Diff for: src/Samples/JetStreamStarter/JetStreamStarter.cs

@@ -12,8 +12,11 @@
 // limitations under the License.
 
 using System;
+using System.Threading;
 using NATS.Client;
 using NATS.Client.Internals;
+using NATS.Client.JetStream;
+using NATS.Client.KeyValue;
 
 namespace NATSExamples
 {
@@ -42,7 +45,7 @@ static void Main(string[] args)
             {
                 Console.WriteLine("Connection closed.");
             };
-           
+            
             Console.WriteLine($"Connecting to '{opts.Url}'");
 
             using (IConnection c = new ConnectionFactory().CreateConnection(opts))