public suspend fun <T> SingleSource<T>.await(): T = suspendCancellableCoroutine { cont ->
    subscribe(object : SingleObserver<T> {
        override fun onSubscribe(d: Disposable) { cont.disposeOnCancellation(d) }
        override fun onSuccess(t: T) { cont.resume(t) }
        override fun onError(error: Throwable) { cont.resumeWithException(error) }
    })
}