The connection should emit a WindowUpdated event on INITIAL_WINDOW_SIZE change

I think the connection should emit a WindowUpdated event on receipt of a settings frame that changes the INITIAL_WINDOW_SIZE. This is because this frame is valid after the receipt of headers and hence it implicitly updates the window (see _flow_control_change_from_settings). Without emitting this frame implementations have to specifically look for this settings change and respond appropriately themselves.

(I'll implement this, just wanted to get views on whether this is the correct thing to do).

从 h2/connection.py 中的 _flow_control_change_from_settings 开始，issue 将其标识为相关的流控制路径。在进行更改之前，跟踪 settings-frame 处理目前如何暴露 connection events，并检查周围行为。完成标准是：更改 INITIAL_WINDOW_SIZE 会产生一个 WindowUpdated event，同时保留其他 settings 的现有行为。