watchKioskMode function
Returns the stream with KioskMode.
The initial value of the stream will always be from getKioskMode.
Since Android doesn't allow subscribing to lock task mode changes,
a mode is queried every time with a period of androidQueryPeriod
.
Implementation
Stream<KioskMode> watchKioskMode({
Duration androidQueryPeriod = const Duration(seconds: 5),
}) =>
Stream.fromFuture(getKioskMode())
.merge(_getKioskModeStream(androidQueryPeriod));