in src/main/java/com/spotify/futures/ConcurrencyLimiter.java [50:58]
private ConcurrencyLimiter(final Executor executor, int maxConcurrency, int maxQueueSize) {
this.executor = executor;
this.maxConcurrency = maxConcurrency;
this.maxQueueSize = maxQueueSize;
Preconditions.checkArgument(maxConcurrency > 0);
Preconditions.checkArgument(maxQueueSize > 0);
this.queue = new ArrayBlockingQueue<>(maxQueueSize);
this.limit = new Semaphore(maxConcurrency);
}