The deciding factor lies in the nature of signal being transmitted.决定因素在于传输的信号的性质。
Implementations of filters for messages transmitted over a peer channel must be derived from this class.为通过对等通道传输的消息而实现的筛选器必须派生自此类。
Window size determines the amount of data that can be transmitted at one time before the destination responds with an acknowledgment.视窗大小是表示在目的地端回应确认讯号之前可以一口气传送的资料量，这是就决定好了。
