getPossibleOffsets() {
    if (!this.isValid || this.isOffsetFixed) {
      return [this];
    }
    const dayMs = 86400000;
    const minuteMs = 60000;
    const localTS = objToLocalTS(this.c);
    const oEarlier = this.zone.offset(localTS - dayMs);
    const oLater = this.zone.offset(localTS + dayMs);

    const o1 = this.zone.offset(localTS - oEarlier * minuteMs);
    const o2 = this.zone.offset(localTS - oLater * minuteMs);
    if (o1 === o2) {
      return [this];
    }
    const ts1 = localTS - o1 * minuteMs;
    const ts2 = localTS - o2 * minuteMs;
    const c1 = tsToObj(ts1, o1);
    const c2 = tsToObj(ts2, o2);
    if (
      c1.hour === c2.hour &&
      c1.minute === c2.minute &&
      c1.second === c2.second &&
      c1.millisecond === c2.millisecond
    ) {
      return [clone(this, { ts: ts1 }), clone(this, { ts: ts2 })];
    }
    return [this];
  }
Get those DateTimes which have the same local time as this DateTime, but a different offset from UTC
in this DateTime's zone. During DST changes local time can be ambiguous, for example
`2023-10-29T02:30:00` in `Europe/Berlin` can have offset `+01:00` or `+02:00`.
This method will return both possible DateTimes if this DateTime's local time is ambiguous.
@returns {DateTime[]}