@Override
    public LogEntry getEntry(final long index) {
        if (index >= this.thresholdIndex) {
            return this.newLogStorage.getEntry(index);
        }
        if (isOldStorageExist()) {
            return this.oldLogStorage.getEntry(index);
        }
        return null;
    }
HybridLogStorage is used to be compatible with new and old logStorage
@author hzh (642256541@qq.com)
jraft-extension/java-log-storage-impl/src/main/java/com/alipay/sofa/jraft/storage/HybridLogStorage.java