@SuppressWarnings("unchecked")
    protected <T extends Object> T readData(final String path, final Stat stat, final boolean watch) {
        byte[] data = retryUntilConnected(new Callable<byte[]>() {

            @Override
            public byte[] call() throws Exception {
                return _connection.readData(path, stat, watch);
            }
        });
        return (T) derializable(data);
    }
Returns a mutex all zookeeper events are synchronized aginst. So in case you need to do something without getting
any zookeeper event interruption synchronize against this mutex. Also all threads waiting on this mutex object
will be notified on an event.

@return the mutex.
shared/common/src/main/java/com/alibaba/otter/shared/common/utils/zookeeper/ZkClientx.java