@Override
    public ConfigurationEntry getConfiguration(final long index) {
        this.readLock.lock();
        try {
            return this.configManager.get(index);
        } finally {
            this.readLock.unlock();
        }
    }
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