生产者，消费者线程并发进行，生产者发现缓冲区满了则唤醒消费者，自己睡眠。消费者发现缓冲区空了，唤醒生产者，自己睡眠。-The producer, the consumer thread, producers have found that the buffer is full, wake up the consumers, their sleep. Consumers find the buffer is empty, awaken the producers, their sleep.