code: public AnyDelete addFamily(String family, long timestamp) {
          delete.addFamily(toFamilyQualifierBytes(family), timestamp);
  
          return this;
      }
docs: Delete all columns of the specified family with a timestamp less than
  or equal to the specified timestamp.
  <p>
  Overrides previous calls to deleteColumn and deleteColumns for the
  specified family.
  
  @param family
  @param timestamp
  @return