RegisterCallbackHandler typedef

RegisterCallbackHandler = ZoneCallback<R> Function<R>(Zone self, ZoneDelegate parent, Zone zone, R f())

The type of a custom Zone.registerCallback implementation function.

Receives the Zone that the handler was registered on as self, a delegate forwarding to the handlers of self's parent zone as parent, and the current zone where the error was uncaught as zone, which will have self as a parent zone.

The function f is the function which was passed to the Zone.registerCallback of zone.

The handler should return either the function f or another function replacing f, typically by wrapping f in a function which does something extra before and after invoking f

The function must only access zone-related functionality through self, parent or zone. It should not depend on the current zone (Zone.current).


typedef RegisterCallbackHandler = ZoneCallback<R> Function<R>(
    Zone self, ZoneDelegate parent, Zone zone, R Function() f);