WCF客户端"使用"块问题的最佳解决方法是什么？

MyServiceClient client = new MyServiceClient();
try
{
    // Call WCF service operations here
}
finally
{
    if (client.State == CommunicationState.Faulted)
    {
        client.Abort();
    }
    else
    {
        client.Close();
    }
}

using (MyServiceClient client = new MyServiceClient())
{
    // Call WCF service operations here
}

MyServiceClient client = new MyServiceClient();
client.InnerChannel.OperationTimeout = new TimeSpan(0, 0, 30); // Set operation timeout
client.ClientCredentials.UserName.UserName = "username"; // Set user name
client.ClientCredentials.UserName.Password = "password"; // Set password
client.Open(); // Open the client