@Override
    public long wait(final long expectedLastLogIndex, final NewLogCallback cb, final Object arg) {
        final WaitMeta wm = new WaitMeta(cb, arg, 0);
        return notifyOnNewLog(expectedLastLogIndex, wm);
    }
Adds event to disk queue, NEVER call it in lock.
@param done
@param type
jraft-core/src/main/java/com/alipay/sofa/jraft/storage/impl/LogManagerImpl.java