optimized the unit test TestCloseAfterSend

Author: kerryjiang

test/SuperSocket.Tests/MainTest.cs

@@ -418,22 +418,22 @@ public async Task TestCloseAfterSend(Type hostConfiguratorType)
                     await s.CloseAsync(CloseReason.LocalClosing);
                 }).BuildAsServer() as IServer)
             {            
-                Assert.True(await server.StartAsync());
+                Assert.True(await server.StartAsync(TestContext.Current.CancellationToken));
                 Assert.Equal(0, server.SessionCount);
 
                 var client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
-                await client.ConnectAsync(hostConfigurator.GetServerEndPoint());                
+                await client.ConnectAsync(hostConfigurator.GetServerEndPoint(), TestContext.Current.CancellationToken);                
                 using (var stream = await hostConfigurator.GetClientStream(client))
                 using (var streamReader = new StreamReader(stream, Utf8Encoding, true))
                 using (var streamWriter = new StreamWriter(stream, Utf8Encoding, 1024 * 1024 * 4))
                 {
                     await streamWriter.WriteAsync("Hello World\r\n");
-                    await streamWriter.FlushAsync();
-                    var line = await streamReader.ReadLineAsync();
+                    await streamWriter.FlushAsync(TestContext.Current.CancellationToken);
+                    var line = await streamReader.ReadLineAsync(TestContext.Current.CancellationToken);
                     Assert.Equal("Hello World", line);
                 }
 
-                await server.StopAsync();
+                await server.StopAsync(TestContext.Current.CancellationToken);
             }
         }