"share with you" is very slow

[tobiasKaminsky]

On our c.nc.c "share with you" is very slow and probably needs a review how to get this faster.

Ref: https://github.com/nextcloud-gmbh/sysadmin/issues/2372

@provokateurin @icewind1991

[szaimen]

@tobiasKaminsky is this issue public by purpose?