/// call resulted in SUCCESS or DELEGATION. Otherwise this method
/// does nothing.
///
+ /// \note The additional RRsets returned via method are limited to
+ /// ones contained in the zone which the corresponding find/findAll
+ /// call searched (possibly including glues under a zone cut where
+ /// they are applicable). If the caller needs to get out-of-zone
+ /// additional RRsets, it needs to explicitly finds them by
+ /// identifying the corresponding zone and calls \c find() for it.
+ ///
/// \param requested_types A vector of RR types for desired additional
/// RRsets.
/// \param result A vector to which any found additional RRsets are