private List<HRegion> getRegionsToFlush(String table) throws IOException {
    return (List<HRegion>) rss.getRegions(TableName.valueOf(table));
  }
Get the list of regions to flush for the table on this server It is possible that if a region
moves somewhere between the calls we'll miss the region.
@return the list of online regions. Empty list is returned if no regions.
hbase-server/src/main/java/org/apache/hadoop/hbase/procedure/flush/RegionServerFlushTableProcedureManager.java