code: private static <ReqT, RespT> ServerCallHandler<ReqT, RespT> asyncStreamingRequestCall(
        StreamingRequestMethod<ReqT, RespT> method) {
      return new StreamingServerCallHandler<>(method);
    }
docs: Creates a {@link ServerCallHandler} for a streaming request call method of the service.
  
  @param method an adaptor to the actual method on the service implementation.