CoroutineAwaitRetrofitCall

sealed class Result<T>
class SuccessfulResult<T>(val responseBody: T): Result<T>()
class UnsuccessfulResult<T>(val response: Response<T>?): Result<T>()
class ExceptionalResult<T>(val throwable: Throwable?): Result<T>()

suspend fun <T : Any> Call<T>.awaitResult(): Result<T> {
    return suspendCancellableCoroutine { continuation ->
        continuation.invokeOnCancellation {
            cancel()
        }
        enqueue(object : Callback<T> {
            override fun onResponse(call: Call<T>, response: Response<T>) {
                val body = response.body()
                continuation.resume(
                    if (response.isSuccessful && body != null)
                        SuccessfulResult(body)
                    else
                        UnsuccessfulResult(response)
                )
            }

            override fun onFailure(call: Call<T>, t: Throwable) {
                continuation.resume(ExceptionalResult(t))
            }
        })
    }
}