def window_update(wsi)
      @recv_remaining_window += wsi
      sid = (Stream === self) ? self.id : 0
      send_immediately Frame::WindowUpdate.new(sid, wsi)
    end
def window_update(wsi)
      @recv_remaining_window += wsi
      sid = (Stream === self) ? self.id : 0
      send_immediately Frame::WindowUpdate.new(sid, wsi)
    end
Increases receiving window size. Sends WINDOW_UPDATE frame to the peer.
 @param wsi [Integer] The amount to increase receiving window size. The legal range is 1 to 2^32-1.