code: public static void addHttp2ToHttpHeaders(int streamId, Http2Headers sourceHeaders,
                      FullHttpMessage destinationMessage, boolean addToTrailer) throws Http2Exception {
          addHttp2ToHttpHeaders(streamId, sourceHeaders,
                  addToTrailer ? destinationMessage.trailingHeaders() : destinationMessage.headers(),
                  destinationMessage.protocolVersion(), addToTrailer, destinationMessage instanceof HttpRequest);
      }
docs: Translate and add HTTP/2 headers to HTTP/1.x headers.
  
  @param streamId The stream associated with {@code sourceHeaders}.
  @param sourceHeaders The HTTP/2 headers to convert.
  @param destinationMessage The object which will contain the resulting HTTP/1.x headers.
  @param addToTrailer {@code true} to add to trailing headers. {@code false} to add to initial headers.
  @throws Http2Exception If not all HTTP/2 headers can be translated to HTTP/1.x.
  @see #addHttp2ToHttpHeaders(int, Http2Headers, HttpHeaders, HttpVersion, boolean, boolean)