并发锁
ReentrantReadWriteLock：ProcessQueue.treeMapLock
ReentrantLock: ProcessQueue.consumeLock
AtomicLong: ProcessQueue.msgCount、msgSize
Semphore: SemaphoreReleaseOnlyOnce
在SemaphoreReleaseOnlyOnce中使用AtomicBoolean实现一个SemaphoreReleaseOnlyOnce只被释放一次
// 信号量，限制正在进行的异步请求的最大数量(65535)，从而保护系统内存占用。
NettyRemotingAbstract.semaphoreAsync
NettyRemotingAbstract#invokeAsyncImpl
-> boolean acquired = this.semaphoreAsync.tryAcquire(timeoutMillis, TimeUnit.MILLISECONDS);
-> acquired为true才会调用发送请求
CountDownLatch：CountDownLacth2、responseTable
并发工具
ConcurrentHashMap
CompletableFuture
LinkedBlockingQueue
PriorityBlockingQueue
ArrayBlockingQueue
