Batch actor with coroutines

batch.kt

    private inline fun <T> createBatchActor(context: CoroutineContext = CommonPool,
                                            parent: Job? = null,
                                            maxSize: Int = 100,
                                            maxTime: Int = 500,
                                            crossinline block: (List<T>) -> Unit): SendChannel<T> {
        return actor(context, parent = parent) {
            val batch = ArrayList<T>(maxSize)
            var deadline = 0L // deadline for sending this batch to callback block

            while(true) {
                // when deadline is reached or size is exceeded, pass the batch to the callback block
                val remainingTime = deadline - System.currentTimeMillis()
                if (batch.isNotEmpty() && remainingTime <= 0 || batch.size >= maxSize) {
                    Timber.d("Processing batch: ${batch.size}")
                    block(batch.toList())
                    batch.clear()
                    continue
                }

                // wait until items is received or timeout reached
                select<Unit> {
                    // when received -> add to batch
                    channel.onReceive {
                        batch.add(it)
                        //Timber.d("Adding user to batch: ${batch.size}")
                        // init deadline on first item added to batch
                        if (batch.size == 1) deadline = System.currentTimeMillis() + maxTime
                    }
                    // when timeout is reached just finish select, note: no timeout when batch is empty
                    if (batch.isNotEmpty()) onTimeout(remainingTime.orZero()) {}
                }

                if (!isActive) break
            }
        }
    }

sample.kt

        val userActor = createBatchActor<User>(activeUsersContext, parent = connectJob,
                maxSize = 500, maxTime = 1000) { users ->
          // DO something wiht the batched User list
        }

        userActor.send(user)