Node.SIGNAL 这个是什么意思？是后继节点对应的线程需要运行？还是自己这个节点对应的线程等待被唤醒？
学习是最好的投资！
waitStatus value to indicate successor's thread needs unparking后续的节点需要被唤醒
waitStatus value to indicate successor's thread needs unparking
waitStatus value to indicate successor's thread needs unparking后续的节点需要被唤醒