public static boolean isRefOnlyScan(Scan scan) {
    byte[] refOnly = scan.getAttribute(MobConstants.MOB_SCAN_REF_ONLY);
    try {
      return refOnly != null && Bytes.toBoolean(refOnly);
    } catch (IllegalArgumentException e) {
      return false;
    }
  }
Indicates whether it's a reference only scan. The information is set in the attribute
"hbase.mob.scan.ref.only" of scan. If it's a ref only scan, only the cells with ref tag are
returned.
@param scan The current scan.
@return True if it's a ref only scan.
hbase-server/src/main/java/org/apache/hadoop/hbase/mob/MobUtils.java