probably dont want to instantiate this yourself
Returns the Net::OAI::Header object for the OAI header element that
accompanied the record.
metadata() =head2 recorddata()
Returns the object (SAX Handler!) used or created by the metadataHandler
rsp. recordHandler filter class at the moment the OAI::Record was created,
namely right after parsing encounters the closing OAI record tag.
In the case of ListRecords requests, a clone of the OAI::record is immediately
created (by means of Storable) thus on processing by the next() method these
metadata() rsp. recorddata() methods will return clones of the original
handler object taken at the moment described above.
Will be undef when no corresponding option was provided.
Access to the actual data if desired has to be provided by the Handler class.
Note that in the case of deleted records the record element of the OAI-PMH response
must not contain a metadata container and therefore the metadataHandler
for that record will never have been active at all.