code: public DateTimeFormatterBuilder appendTimeZoneOffset(
              String zeroOffsetText, boolean showSeparators,
              int minFields, int maxFields) {
          return append0(new TimeZoneOffset
                         (zeroOffsetText, zeroOffsetText, showSeparators, minFields, maxFields));
      }
docs: Instructs the printer to emit text and numbers to display time zone
  offset from UTC. A parser will use the parsed time zone offset to adjust
  the datetime.
  <p>
  If zero offset text is supplied, then it will be printed when the zone is zero.
  During parsing, either the zero offset text, or the offset will be parsed.
  
  @param zeroOffsetText  the text to use if time zone offset is zero. If
  null, offset is always shown.
  @param showSeparators  if true, prints ':' separator before minute and
  second field and prints '.' separator before fraction field.
  @param minFields  minimum number of fields to print, stopping when no
  more precision is required. 1=hours, 2=minutes, 3=seconds, 4=fraction
  @param maxFields  maximum number of fields to print
  @return this DateTimeFormatterBuilder, for chaining