Kotlin Coroutines でリトライをしながら通信を試行する with RxJava 2

MainActivity.kt

package com.example.tomoyashibata.myapplication

import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.coroutines.experimental.CommonPool
import kotlinx.coroutines.experimental.android.UI
import kotlinx.coroutines.experimental.launch
import kotlinx.coroutines.experimental.rx2.rxSingle
import java.net.URL
import kotlin.coroutines.experimental.suspendCoroutine


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

        launch(UI) {
            try {
                val bitmap = this@MainActivity.loadAvatarImage()
                this@MainActivity.avatarImageView.setImageBitmap(bitmap)
            } catch (e: Exception) {
                // エラーを Toast で表示
                Toast.makeText(this@MainActivity, e.toString(), Toast.LENGTH_LONG).show()
            }
        }

    }

    private suspend fun loadAvatarImage(): Bitmap = suspendCoroutine { cont ->
        // URL から末尾の .jpg を取り除いてわざとエラーが起こるようにしている
        val urlConnection = URL("https://pbs.twimg.com/profile_images/637494283365298177/J0t3qvlm_400x400").openConnection()

        rxSingle(CommonPool) {
            urlConnection.connect()
            val stream = urlConnection.getInputStream()
            return@rxSingle BitmapFactory.decodeStream(stream)
        }
            .retry(10)
            .subscribe({
                cont.resume(it)
            }, {
                cont.resumeWithException(it)
            })
    }
}