code: def test_grpc_gateway_runtime_handle_messages_linear(
      linear_graph_dict, monkeypatch, protocol
  ):
      monkeypatch.setattr(
          networking.GrpcConnectionPool,
          "send_requests_once",
          DummyMockConnectionPool.send_requests_once,
      )
      monkeypatch.setattr(
          networking.GrpcConnectionPool,
          "send_discover_endpoint",
          DummyMockConnectionPool.send_discover_endpoint,
      )
      port = random_port()
  
      def client_validate(client_id: int):
          responses = client_send(client_id, port, protocol)
          assert len(responses) > 0
          assert len(responses[0].docs) == 1
          assert (
              responses[0].docs[0].text
              == f"client{client_id}-Request-client{client_id}-deployment0-client{client_id}-deployment1-client{client_id}-deployment2-client{client_id}-deployment3"
          )
  
      p = multiprocessing.Process(
          target=create_runtime,
          kwargs={
              "protocol": protocol,
              "port": port,
              "graph_dict": linear_graph_dict,
          },
      )
      p.start()
      time.sleep(1.0)
      client_processes = []
      for i in range(NUM_PARALLEL_CLIENTS):
          cp = multiprocessing.Process(
              target=client_validate, kwargs={"client_id": i}
          )
          cp.start()
          client_processes.append(cp)
  
      for cp in client_processes:
          cp.join()
      p.terminate()
      p.join()
      for cp in client_processes:
          assert cp.exitcode == 0
  
imports: import asyncio
  import copy
  import multiprocessing
  import time
  from typing import Dict
  import pytest
  from docarray import Document, DocumentArray
  from jina.helper import random_port
  from jina.parsers import set_gateway_parser
  from jina.serve import networking
  from jina.serve.runtimes.asyncio import AsyncNewLoopRuntime
  from jina.serve.runtimes.gateway.request_handling import GatewayRequestHandler
  from jina.types.request.data import DataRequest
label_desc: Use image node_id 8 for calling a global function with example usage: test_grpc_gateway_runtime_handle_messages_linear(linear_graph_dict, monkeypatch, protocol) without return types