Provide batch_callback_once in Scope

[ctron]

Describe the feature you'd like

For the callback method of the Scope struct a method named callback_once exists, which accepts an FnOnce parameter.

I think a similar method (e.g. batch_callback_once) should be provided for the batch_callback function.

Is your feature request related to a problem? Please describe. (Optional)

A closure which gets called only once, makes is easier to move (instead of clone) data. So using a FnOnce would make life easier in some situations.

Describe alternatives you've considered (Optional)

Additional context (Optional)

Questionnaire

• I'm interested in implementing this myself but don't know where to start
• I would like to add this feature
• I don't have time to add this right now, but maybe later

[siku2]

Agreed, since we already have the callback_once method I see no reason why we shouldn't provide the same for batch_callback.