Can't force whenSaveable to run after save

[Kirby]

Affected version

2.3.7

Sometimes it is useful to run code after an entity has been saved depending of the state of the entity before saving.

There already is method whenSaveable() that allows to do so if called while a write is already taking place - but it is not (nicely) possible to force the callback to be executed after the entity is saved.

Could the method get a parameter to force running the callback after save?