Reducing the Stream Window Size / 减小流的窗口大小

A receiver that wishes to use a smaller flow-control window than the current size can send a new SETTINGS frame. However, the receiver MUST be prepared to receive data that exceeds this window size, since the sender might send data that exceeds the lower limit prior to processing the SETTINGS frame.

如果接收端希望使用比当前值小的流量控制窗口，可以发送一个新的 SETTINGS 帧。但是，接收端必须准备好接收超出该窗口值的数据，因为可能在处理 SETTIGNS 帧之前，发送端已经发送了超出该较小窗口值的数据。

After sending a SETTINGS frame that reduces the initial flow-control window size, a receiver MAY continue to process streams that exceed flow-control limits. Allowing streams to continue does not allow the receiver to immediately reduce the space it reserves for flow-control windows. Progress on these streams can also stall, since WINDOW_UPDATE frames are needed to allow the sender to resume sending. The receiver MAY instead send a RST_STREAM with an error code of FLOW_CONTROL_ERROR for the affected streams.

发送了可以减小初始流量控制窗口大小的 SETTIGNS 帧以后，接收端可以继续处理超出流量控制限制的流。允许流继续意味着不允许接收端立即减小它为流量控制窗口保留的空间。因为需要 WINDOW_UPDATE 帧允许发送端重新开始发送数据，对这些流的处理也可以中止。对于受影响的流，接收端可以代替发送一个 RST_STREAM 帧，携带错误码 FLOW_CONTROL_ERROR。