code: @Override
      public Object onRequest(Object request, Map<String,String> headers) {
          if (headers.containsKey(Listener.METAINFO_HTTP_METHOD)) {
              Tracing tracing = TraceHelper.getTracing("mdw-service");
              HttpTracing httpTracing = HttpTracing.create(tracing);
              handler = HttpServerHandler.create(httpTracing, new ServerAdapter());
              extractor = httpTracing.tracing().propagation().extractor(ServerAdapter.ServerRequest::getHeader);
              span = handler.handleReceive(extractor, new ServerAdapter.ServerRequest(headers));
              scope = httpTracing.tracing().tracer().withSpanInScope(span);
          }
          return null;
      }
docs: Only for HTTP services.