code: @Nonnull
    public Query endAt(Object... fieldValues) {
      QueryOptions newOptions = new QueryOptions(options);
      newOptions.endCursor = createCursor(newOptions.fieldOrders, fieldValues, false);
      return new Query(firestore, path, newOptions);
    }
docs: Creates and returns a new Query that ends at the provided fields relative to the order of the
  query. The order of the field values must match the order of the order by clauses of the query.
  
  @param fieldValues The field values to end this query at, in order of the query's order by.
  @return The created Query.