Previously, if automatic window update is enabled (which is default),
after window size is set to 0 by
nghttp2_session_set_local_window_size, once the receiving window is
exhausted, even after window size is increased by
nghttp2_session_set_local_window_size, no more data cannot be
received. This is because nghttp2_session_set_local_window_size does
not submit WINDOW_UPDATE. It is only triggered when new data arrives
but since window is filled up, no more data cannot be received, thus
dead lock happens.
This commit fixes this issue. nghttp2_session_set_local_window_size
submits WINDOW_UPDATE if necessary.
https://github.com/curl/curl/issues/4939
2ec585518e