code: @Test public void windowUpdateRoundTrip() throws IOException {
    OkBuffer frame=new OkBuffer();
    final long expectedWindowSizeIncrement=0x7fffffff;
    frame.writeShort(4);
    frame.writeByte(Http20Draft09.TYPE_WINDOW_UPDATE);
    frame.writeByte(0);
    frame.writeInt(expectedStreamId);
    frame.writeInt((int)expectedWindowSizeIncrement);
    assertEquals(frame,windowUpdate(expectedWindowSizeIncrement));
    FrameReader fr=new Http20Draft09.Reader(frame,4096,false);
    fr.nextFrame(new BaseTestHandler(){
      @Override public void windowUpdate(    int streamId,    long windowSizeIncrement){
        assertEquals(expectedStreamId,streamId);
        assertEquals(expectedWindowSizeIncrement,windowSizeIncrement);
      }
    }
  );
  }
  