Improve item details UI performance

[mvasilak]

Improves UI performance for item details. When there is a large number of sizable notes, e.g. ones created from annotations, scrolling becomes sluggish, and opening attachments from the details view causes the app to hang as the loading of the file is very slow.

[michalrentka]

Just to confirm, the "performance improvement" was moving the slow parts to background? :) I didn't know we could do data source snapshot updates in background, doesn't it break anything? Otherwise if this helps then great.

[mvasilak]

In this case, both this and the snapshot memory reduction are performance improvements, but the latter has a larger effect.

Using a background queue for diffable data source updates has been suggested since its introduction. The framework handles the snapshot application in the main queue, and all business logic can be safely done in the background.

[michalrentka]

Using a background queue for diffable data source updates has been suggested since its introduction. The framework handles the snapshot application in the main queue, and all business logic can be safely done in the background.

Good to know, we could definitely move all diffable data source interactions to background then. Feel free to create a ticket for it.

[michalrentka]

(Sorry, I added comments some time ago and forgot to submit them)