beforeUnloadEvent constant

EventStreamProvider<BeforeUnloadEvent> const beforeUnloadEvent = const _BeforeUnloadEventStreamProvider('beforeunload')

Static factory designed to expose beforeunload events to event handlers that are not necessarily instances of Window.

See EventStreamProvider for usage information.

Implementation 

static const EventStreamProvider<BeforeUnloadEvent> beforeUnloadEvent =
    const _BeforeUnloadEventStreamProvider('beforeunload')