task.kt

suspend inline fun <reified T> Task<T>.await(): T = suspendCoroutine {
    addOnCompleteListener { task ->
        if (task.isSuccessful) {

            // Black magic to make it return Unit instead of null
            if (Unit is T) {
                it.resume(Unit)
            } else {
                it.resume(task.result!!)
            }
            return@addOnCompleteListener
        }
        task.exception?.apply { it.resumeWithException(this) }
    }
}