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).