code: List<ZoneOffset> getValidOffsets() {
          if (isGap()) {
              return Collections.emptyList();
          }
          return Arrays.asList(getOffsetBefore(), getOffsetAfter());
      }
docs: Gets the valid offsets during this transition.
  <p>
  A gap will return an empty list, while an overlap will return both offsets.
  
  @return the list of valid offsets