docs: @Nonnull
    public Query whereLessThan(@Nonnull FieldPath fieldPath, @Nonnull Object value) {
      Preconditions.checkState(
          options.startCursor == null && options.endCursor == null,
          "Cannot call whereLessThan() after defining a boundary with startAt(), "
              + "startAfter(), endBefore() or endAt().");
      QueryOptions newOptions = new QueryOptions(options);
      newOptions.fieldFilters.add(new ComparisonFilter(fieldPath, LESS_THAN, value));
      return new Query(firestore, path, newOptions);
    }