val networkism = Networkism.instance(context)
networkism.checkConnectionAsLiveData(lifecycleScope)
    .observe(this, Observer { networkResult ->
        if (networkResult.isConnected) {
            // connected
        } else {
            // disconnected
        }
    })

// extend activity/fragment to `NetworkListener`
class MainActivity : AppCompatActivity(), NetworkismListener {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // init lifecycle scope from 'androidx.lifecycle:lifecycle-runtime-ktx'
        val networkism = Networkism.instance(this)
        networkism.setNetworkismListener(lifecycleScope, this)
    }

    override fun connectivityAvailable(counter: NetworkismResult.Counter?) {
        // view for connection available
        txt_log.text = "connect"
    }

    override fun connectivityLost() {
        // view for disconnect
        txt_log.text = "disconnect"
    }
}

fun getUsers(page: Int = 1, networkism: Networkism) = viewModelScope.launch {
    networkism.checkConnection()
        .map { retrofit.getUser(page) }
        .map { it.data.map { d -> d.lastName } }
        .collect {
            _users.postValue(it)
        }
}

val networkism = Networkism.instance(context)
networkism.withConnectionBuilder {
      okHttpClient = OkHttpClient()
      url = "https://www.google.com"
  }