private void snapshotClosedRegions(MasterProcedureEnv env) throws IOException {
    List<RegionInfo> regions = getDefaultRegionReplica(env).collect(Collectors.toList());
    snapshotSplitOrClosedRegions(env, regions, "ClosedRegionsSnapshotPool");
  }
A procedure used to take snapshot on tables.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/SnapshotProcedure.java