code: @Override
      public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
          if (getEmbeddedHttp2Exception(cause) != null) {
              // Some exception in the causality chain is an Http2Exception - handle it.
              onError(ctx, false, cause);
          } else {
              super.exceptionCaught(ctx, cause);
          }
      }
docs: Handles {@link Http2Exception} objects that were thrown from other handlers. Ignores all other exceptions.