jeziellago

fun performRequest() {
    api.request(
        call = service.getUser("jeziellago"), 
        onSuccess = { user -> // fazer algo com o usuário }, 
        onFailure = { error -> // exibir o erro }
    )
}

jeziellago

import kotlinx.coroutines.experimental.CommonPool
import kotlinx.coroutines.experimental.android.UI
import kotlinx.coroutines.experimental.launch
import kotlinx.coroutines.experimental.withContext
import retrofit2.Call
import retrofit2.Retrofit
...

class Api {
  ...

jeziellago

fun load() = launch(UI) {
    try {
        val result = withContext(CommonPool) { // work! }
        ...
    } catch (e: IOException) { // exception que pode gerar
      // exception here!
    }
}

jeziellago

fun loadTask() = launch(UI) { // executa na main thread 
  // executa em uma thread separada
  val result1 = withContext(CommonPool) { // work! }
  // executa na mesma thread
  val result2 = withContext(Unconfined) { // work! }
}