void restoreSnapshot(Configuration conf, String snapshotName, Path rootDir, Path restoreDir,
    FileSystem fs) throws IOException {
    RestoreSnapshotHelper.copySnapshotForScanner(conf, fs, rootDir, restoreDir, snapshotName);
  }
Restore each (snapshot name, restore directory) pair in snapshotToDir
@param conf          configuration to restore with
@param snapshotToDir mapping from snapshot names to restore directories
@param fs            filesystem to do snapshot restoration on
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/MultiTableSnapshotInputFormatImpl.java