OrgNum:    req.Num,
			OrgString: req.String,
			Embedded:  *req,
		}
		return resp, nil
	}
	// Return error
	h2 := NewSingleHandler[*testRequest, *testResponse](handlerTest2, newTestRequest, newTestResponse)
	handler2 := func(req *testRequest) (resp *testResponse, err *RemoteErr) {
		r := RemoteErr(req.String)
		return nil, &r
	}
	errFatal(h1.Register(local, handler1))
	errFatal(h2.Register(local, handler2))

	defer testlogger.T.SetErrorTB(b)()
	errFatal := func(err error) {
		b.Helper()
		if err != nil {
			b.Fatal(err)
		}
	}
	rpc := NewSingleHandler[*testRequest, *testResponse](handlerTest2, newTestRequest, newTestResponse)
	grid, err := SetupTestGrid(n)
	errFatal(err)
	b.Cleanup(grid.Cleanup)
	// Create n managers.
	for _, remote := range grid.Managers {
		// Register a single handler which echos the payload.