If this callback is passed to e_book_sqlite_new(), then
vcards are not stored in the SQLite and instead this callback
is invoked to fetch the vcard.
This callback will be called to fetch results for fully indexed
and optimized queries, and it will also be called while performing
fallback queries against #EContactFields which are not configured
in the #ESourceBackendSummarySetup or default summary fields.
This user callback is called inside a lock,
you must not call the #EBookSqlite API from
this callback.
If this callback is passed to e_book_sqlite_new(), then vcards are not stored in the SQLite and instead this callback is invoked to fetch the vcard.
This callback will be called to fetch results for fully indexed and optimized queries, and it will also be called while performing fallback queries against #EContactFields which are not configured in the #ESourceBackendSummarySetup or default summary fields.