docs: private void getHeadersFromFrame() {
          byte[] hbf = null;
          if (currentFrame.getFrameType() == FrameTypes.HEADERS || currentFrame.getFrameType() == FrameTypes.PUSHPROMISEHEADERS) {
              hbf = ((FrameHeaders) currentFrame).getHeaderBlockFragment();
          } else if (currentFrame.getFrameType() == FrameTypes.CONTINUATION) {
              hbf = ((FrameContinuation) currentFrame).getHeaderBlockFragment();
          }
  
          if (hbf != null) {
              if (headerBlock == null) {
                  headerBlock = new ArrayList<byte[]>();
              }
              headerBlock.add(hbf);
          }
      }