MainActivity.kt

class MainActivity : AppCompatActivity() {

    private val viewModel = UserViewModel()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val adapter = UserAdapter()

        recyclerView.layoutManager = LinearLayoutManager(this)
        recyclerView.adapter = adapter

        viewModel.startUpdates()
    }

    override fun onDestroy() {
        viewModel.stopUpdates()
        super.onDestroy()
    }
}