dragEvent constant
A stream of drag events fired when an element is currently being dragged.
A drag event is added to this stream as soon as the drag begins.
A drag event is also added to this stream at intervals while the drag
operation is still ongoing.
Other resources
Drag and drop sample based on the tutorial from HTML5Rocks. Drag and drop specification from WHATWG.
Implementation
static const EventStreamProvider<MouseEvent> dragEvent =
const EventStreamProvider<MouseEvent>('drag')