public static int getStartOffset(List<? extends RangeMarker> rangeMarkers) {
    LOG.assertTrue(!rangeMarkers.isEmpty());
    int minStart = Integer.MAX_VALUE;
    for (RangeMarker rangeMarker : rangeMarkers) {
      if (!rangeMarker.isValid()) continue;
      int startOffset = rangeMarker.getStartOffset();
      if (startOffset < minStart) minStart = startOffset;
    }
    return minStart == Integer.MAX_VALUE ? -1 : minStart;
  }
public static int getStartOffset(List<? extends RangeMarker> rangeMarkers)