await.kt

public suspend fun <T : Any> Call<T>.await(): T {
    return suspendCancellableCoroutine { continuation ->
        enqueue(object : Callback<T> {
            override fun onResponse(call: Call<T>?, response: Response<T?>) {
                if (response.isSuccessful) {
                    val body = response.body()
                    if (body == null) {
                        continuation.resumeWithException(
                            NullPointerException("Response body is null: $response")
                        )
                    } else {
                        continuation.resume(body)
                    }
                } else {
                    continuation.resumeWithException(HttpException(response))
                }
            }

            override fun onFailure(call: Call<T>, t: Throwable) {
                // Don't bother with resuming the continuation if it is already cancelled.
                if (continuation.isCancelled) return
                continuation.resumeWithException(t)
            }
        })

        registerOnCompletion(continuation)
    }
}