Each asynchronouschannel class defines duplicate API methods for each operation so that either mechanism can be used.
每个异步通道类为每个操作定义API副本，这样可采用任一机制。
2
The asynchronouschannel APIs provide two mechanisms for monitoring and controlling the initiated asynchronous operations.
异步通道API提供两种对已启动异步操作的监测与控制机制。
3
And for those that want to use a pseudo-synchronous style over an asynchronouschannel, please, please, please, see Bobby Woolf's book on Designing Messaging Systems.