public static ConstrainedExecutorService newConstrainedExecutor(
      String name, int maxConcurrency, int queueSize, Executor executor) {
    return new ConstrainedExecutorService(
        name, maxConcurrency, executor, new LinkedBlockingQueue<Runnable>(queueSize));
  }
Factory method to create a new {@code ConstrainedExecutorService} with an unbounded {@link
LinkedBlockingQueue} queue.

@param name Friendly name to identify the executor in logging and reporting.
@param maxConcurrency Maximum number of tasks to execute in parallel on the delegate executor.
@param queueSize Number of items that can be queued before new submissions are rejected.
@param executor Delegate executor for actually running tasks.
@return new {@code ConstrainedExecutorService} instance.
fbcore/src/main/java/com/facebook/common/executors/ConstrainedExecutorService.java