@Override
    public long getMobThreshold() {
      return getStringOrDefault(MOB_THRESHOLD_BYTES, Long::valueOf, DEFAULT_MOB_THRESHOLD);
    }
Set the raw crypto key attribute for the family
@return this (for chained invocation)
hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptorBuilder.java