default Iterable<SnapshotContext> getSnapshotContexts(
      org.apache.hadoop.hive.ql.metadata.Table hmsTable, SnapshotContext since) {
    return Collections.emptyList();
  }
Return snapshot metadata of table snapshots which are newer than the specified.
The specified snapshot is excluded.
@param hmsTable table metadata stored in Hive Metastore
@param since the snapshot preceding the oldest snapshot which should be checked.
             The value null means all should be checked.
@return Iterable of {@link SnapshotContext}.
ql/src/java/org/apache/hadoop/hive/ql/metadata/HiveStorageHandler.java