public void Invoke_TaskAsyncReference()
        {
            var          ctx      = new ServerSideAsyncDomainContext(TestURIs.ServerSideAsync);
            const string message  = "client";
            const string expected = "Hello client";

            var invokeOp = ctx.Greet(message);

            this.EnqueueCompletion(() => invokeOp);
            this.EnqueueCallback(() =>
            {
                Assert.IsNull(invokeOp.Error);
                Assert.AreEqual(expected, invokeOp.Value);
            });
            this.EnqueueTestComplete();
        }