Remove usings in first BlockingCollection example (#4264)

using statement not needed with Task when using Task.WhenAll or Task.WaitAll  after .NET 4.5

Author: gurustron

samples/snippets/csharp/VS_Snippets_CLR_System/system.collections.concurrent.blockingcollection/cs/blockingcoll.cs

@@ -27,32 +27,30 @@ public static async Task BC_AddTakeCompleteAdding()
         using (BlockingCollection<int> bc = new BlockingCollection<int>())
         {
             // Spin up a Task to populate the BlockingCollection
-            using (Task t1 = Task.Run(() =>
+            Task t1 = Task.Run(() =>
             {
                 bc.Add(1);
                 bc.Add(2);
                 bc.Add(3);
                 bc.CompleteAdding();
-            }))
+            });
+
+            // Spin up a Task to consume the BlockingCollection
+            Task t2 = Task.Run(() =>
             {
-                // Spin up a Task to consume the BlockingCollection
-                using (Task t2 = Task.Run(() =>
+                try
                 {
-                    try
-                    {
-                        // Consume consume the BlockingCollection
-                        while (true) Console.WriteLine(bc.Take());
-                    }
-                    catch (InvalidOperationException)
-                    {
-                        // An InvalidOperationException means that Take() was called on a completed collection
-                        Console.WriteLine("That's All!");
-                    }
-                }))
+                    // Consume consume the BlockingCollection
+                    while (true) Console.WriteLine(bc.Take());
+                }
+                catch (InvalidOperationException)
                 {
-                    await Task.WhenAll(t1, t2);
+                    // An InvalidOperationException means that Take() was called on a completed collection
+                    Console.WriteLine("That's All!");
                 }
-            }
+            });
+
+            await Task.WhenAll(t1, t2);
         }
     }
 }