docs: public static <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall(
          Context context,
          ServerCall<ReqT, RespT> call,
          Metadata headers,
          ServerCallHandler<ReqT, RespT> next) {
      Context previous = context.attach();
      try {
        return new ContextualizedServerCallListener<>(
            next.startCall(call, headers),
            context);
      } finally {
        context.detach(previous);
      }
    }