Modify RegisterEthService()

The next thing we'll do is modify RegisterEthService so that it accepts the mevlink stream as a parameter and and passes it to the eth.New() call in cmd/utils/flags.go. We'll import the streamer package, define the parameter as *mlstreamergo.Streamer and pass it to eth.New():

// cmd/utils/flags.go

func RegisterEthService(stack *node.Node, cfg *ethconfig.Config, mlstream *mlstreamergo.Streamer) (ethapi.Backend, *eth.Ethereum) {
	if cfg.SyncMode == downloader.LightSync {
		backend, err := les.New(stack, cfg)
		if err != nil {
			Fatalf("Failed to register the Ethereum service: %v", err)
		}
		stack.RegisterAPIs(tracers.APIs(backend.ApiBackend))
		if err := lescatalyst.Register(stack, backend); err != nil {
			Fatalf("Failed to register the Engine API service: %v", err)
		}
		return backend.ApiBackend, nil
	}
	backend, err := eth.New(stack, cfg, mlstream)
	if err != nil {
		Fatalf("Failed to register the Ethereum service: %v", err)
	}
	if cfg.LightServ > 0 {
		_, err := les.NewLesServer(stack, backend, cfg)
		if err != nil {
			Fatalf("Failed to create the LES server: %v", err)
		}
	}
	if err := ethcatalyst.Register(stack, backend); err != nil {
		Fatalf("Failed to register the Engine API service: %v", err)
	}
	stack.RegisterAPIs(tracers.APIs(backend.APIBackend))
	return backend.APIBackend, backend
}