code: public ZoneOffsetTransition getTransition(LocalDateTime localDateTime) {
          Object info = getOffsetInfo(localDateTime);
          return (info instanceof ZoneOffsetTransition ? (ZoneOffsetTransition) info : null);
      }
docs: Gets the offset transition applicable at the specified local date-time in these rules.
  <p>
  The mapping from a local date-time to an offset is not straightforward.
  There are three cases:
  <ul>
  <li>Normal, with one valid offset. For the vast majority of the year, the normal
  case applies, where there is a single valid offset for the local date-time.</li>
  <li>Gap, with zero valid offsets. This is when clocks jump forward typically
  due to the spring daylight savings change from "winter" to "summer".
  In a gap there are local date-time values with no valid offset.</li>
  <li>Overlap, with two valid offsets. This is when clocks are set back typically
  due to the autumn daylight savings change from "summer" to "winter".
  In an overlap there are local date-time values with two valid offsets.</li>
  </ul>
  A transition is used to model the cases of a Gap or Overlap.
  The Normal case will return null.
  <p>
  There are various ways to handle the conversion from a {@code LocalDateTime}.
  One technique, using this method, would be:
  <pre>
  ZoneOffsetTransition trans = rules.getTransition(localDT);
  if (trans == null) {
  // Gap or Overlap: determine what to do from transition
  } else {
  // Normal case: only one valid offset
  zoneOffset = rule.getOffset(localDT);
  }
  </pre>
  
  @param localDateTime  the local date-time to query for offset transition, not null, but null
  may be ignored if the rules have a single offset for all instants
  @return the offset transition, null if the local date-time is not in transition