default List<File> getSnapshotFiles(File latestSnapshotRootDir) {
    return Utils.listAllRegularFilesRecursively(latestSnapshotRootDir);
  }
given a snapshot dir, ask statemachine to provide all snapshot files. By default, it will list
all files recursively under latestSnapshotDir

<p>DataRegion may take snapshot at a different disk and only store a log file containing file
paths. So statemachine is required to read the log file and provide the real snapshot file
paths.

@param latestSnapshotRootDir dir where the latest snapshot sits
@return List of real snapshot files.
iotdb-core/consensus/src/main/java/org/apache/iotdb/consensus/IStateMachine.java