code: public static String toStringForTimeZone(DateTime dateTime, String newZoneId) {
      return dateTimesHelper.toStringForTimeZone(dateTime, newZoneId);
    }
docs: Returns string representation of this date time with a different time zone, preserving the
  millisecond instant.
  
  <p>This method is useful for finding the local time in another time zone, especially for
  filtering.
  
  <p>For example, if this date time holds 12:30 in Europe/London, the result from this method
  with Europe/Paris would be 13:30. You may also want to use this with your network's time zone,
  i.e.
  
  <pre><code> String timeZoneId = networkService.getCurrentNetwork().getTimeZone();
  String statementPart =
  "startDateTime > "
  + DateTimes.toString(apiDateTime, timeZoneId);
  //...
  statementBuilder.where(statementPart);
  </code></pre>
  
  This method is in the same style of {@link
  org.joda.time.DateTime#withZone(org.joda.time.DateTimeZone)}.
  
  @param dateTime the date time to stringify into a new time zone
  @param newZoneId the time zone ID of the new zone
  @return a string representation of the {@code DateTime} in {@code yyyy-MM-dd'T'HH:mm:ss}