code: public void windowUpdateRatio(float ratio) {
          assert ctx == null || ctx.executor().inEventLoop();
          checkValidRatio(ratio);
          windowUpdateRatio = ratio;
      }
docs: The window update ratio is used to determine when a window update must be sent. If the ratio
  of bytes processed since the last update has meet or exceeded this ratio then a window update will
  be sent. This is the global window update ratio that will be used for new streams.
  @param ratio the ratio to use when checking if a {@code WINDOW_UPDATE} is determined necessary for new streams.
  @throws IllegalArgumentException If the ratio is out of bounds (0, 1).