Include / exclude props that dcc.Loading component reacts to

From community issue https://community.plot.ly/t/loading-state-argument-in-dcc-loading/31936

• Probably requires https://github.com/plotly/dash/issues/893 to be fixed
• As part of this issue, we would want to hide loading_state from the generated API for the components – this prop is generated by the renderer and it makes no sense for users to try and do anything with it
• The loading component would now need the list of id/props that are being processed instead of a single prop https://github.com/plotly/dash/blob/dev/dash-renderer/src/TreeContainer.js#L322

New prop(s) for dcc.Loading

• Allow users to provide an inclusion/exclusion list of props that the component will react to to enable it’s “loading state”

[HedgeShot]

This would be really nice. My use case is the following: long callback that returns a “children” with a child that is link to another callback. It makes sense to have dcc.Loading around the long callback but it doesn’t when updating the child. At the moment, dcc.Loading is triggered with both callbacks. Having the possibility to exclude some ids would solve the issue.

[CNFeffery]

@Marc-Andre-Rivet @chriddyp What’s new about this feature so far