Combination of async coroutine and Arrows Either object

either_and_async.kt

override suspend fun execute(query: PostsQuery): Either<Failure, List<Post>> {
        val operation = if (query.forceRefresh) MainSyncOperation else CacheSyncOperation
        return either {
            val posts = !repository.getAll(query = query, operation = operation)
            posts
                .filter { it.featuredImage != null } //we just want posts with featured images
                .map { post ->
                    withContext(coroutineDispatcher) {
                        async {
                            val host: String? = try {
                                URI.create(post.authorUrl).host
                            } catch (e: IllegalArgumentException) {
                                null
                            }
                            if (host.isNullOrBlank()) {
                                post
                            } else {
                                post.copy(
                                    numberOfSubscribers = !getsubsCountUseCase(
                                        SubscribersQuery(host)
                                    ).handleError { 0L })
                            }
                        }
                    }
                }.awaitAll()
        }
    }