code: def test_request_metadata():
      """Test logic on RequestMetadata.
  
      Ensure the default values are set correctly and both is_http_request and
      is_grpc_request returns the correct value. When the _request_protocol is set to
      HTTP, is_http_request should return True and is_grpc_request should return False.
      When the _request_protocol is set to gRPC, is_http_request should return False and
      is_grpc_request should return True.
      """
      request_id = "request-id"
      endpoint = "endpoint"
      request_metadata = RequestMetadata(
          request_id=request_id, endpoint=endpoint
      )
  
      # Ensure the default values are set correctly.
      assert request_metadata.request_id == request_id
      assert request_metadata.endpoint == endpoint
      assert request_metadata.call_method == "__call__"
      assert request_metadata.route == ""
      assert request_metadata.app_name == ""
      assert request_metadata.multiplexed_model_id == ""
      assert request_metadata.is_streaming is False
      assert (
          request_metadata._request_protocol
          == RequestProtocol.UNDEFINED
      )
      assert request_metadata.is_http_request is False
      assert request_metadata.is_grpc_request is False
  
      # is_http_request and is_grpc_request returns the correct values when the
      # _request_protocol is set to HTTP.
      request_metadata._request_protocol = RequestProtocol.HTTP
      assert request_metadata.is_http_request is True
      assert request_metadata.is_grpc_request is False
  
      # is_http_request and is_grpc_request returns the correct values when the
      # _request_protocol is set to gRPC.
      request_metadata._request_protocol = RequestProtocol.GRPC
      assert request_metadata.is_http_request is False
      assert request_metadata.is_grpc_request is True
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_request_metadata() without return types