feat: onDragStart listener for ion-reorder-group

[jwburnside]

Feature Request

Ionic version:
Ionic Framework : @ionic/angular 5.5.3

Describe the Feature Request
It would be great to add onDragStart and onDragEnd events for ion-reorder-group. Currently there is only an event when the drag completes AND the list order has changed.

My use case would be if I have icons contained in the list items I want to hide the icons while the list item is being dragged, then display them once the drag is complete.

Describe Preferred Solution
Add an onDragStart and onDragEnd listener that I can subscribe to which will fire when dragging starts and dragging ends respectively (regardless of if the list order changed).

Describe Alternatives
I don't think there are any alternatives.

Related Code
No related code.

Additional Context
I have not been able to find a workaround for this.

[ihorbond]

+1

[vicatcu]

I have a list that updates once a second. Without the ability to get a callback when the drag starts I can't halt the updates while reorder is occurring to keep the list re-rendering while an item is being dragged.