code: @Nonnull
    public Query startAfter(@Nonnull DocumentSnapshot snapshot) {
      QueryOptions newOptions = new QueryOptions(options);
      newOptions.fieldOrders = createImplicitOrderBy();
      newOptions.startCursor = createCursor(newOptions.fieldOrders, snapshot, false);
      return new Query(firestore, path, newOptions);
    }
docs: Creates and returns a new Query that starts after the provided document (exclusive). The
  starting position is relative to the order of the query. The document must contain all of the
  fields provided in the orderBy of this query.
  
  @param snapshot The snapshot of the document to start after.
  @return The created Query.