@Override
    public void onRecoverDone(final int recoverPosition) {
        final int indexNum = (recoverPosition - this.header.getHeaderSize()) / IndexEntry.INDEX_SIZE;
        this.header.setLastLogIndex(this.header.getFirstLogIndex() + indexNum);
    }
Find the index entry
@param  logIndex the target log index
@return a pair holding this offset and its physical file position.
jraft-extension/java-log-storage-impl/src/main/java/com/alipay/sofa/jraft/storage/file/index/IndexFile.java