Retry function

[jcornaz]

Although it is not really related to coroutines or channels I think it fits this lib because:

• Suspending functions are good fit for calling external API, disk access etc. and all sort of things for which having retry mechanism is often useful.
• One purpose of this project is to make actually easier and pleasant to use coroutines and channels instead of RxJava or equivalent reactive library. And theses reactive library usually provide a retry mechanism.

Implementation example:

suspend inline fun <R> retry(maxAttempts: Int, delayBeforeRetry: Long = 0L, action: () -> R): R {
  require(maxAttempts > 0) { "Invalid max attempts: $maxAttempts" }

  lateinit var exception: Throwable

  repeat(maxAttempts) {
    try {
      return action()
    } catch (t: Throwable) {
      exception = t
      delay(delayBeforeRetry)
    }
  }

  throw exception
}