RegisterUnaryCallbackHandler typedef Null safety

ZoneUnaryCallback<R, T> RegisterUnaryCallbackHandler <R, T>(
  1. Zone self,
  2. ZoneDelegate parent,
  3. Zone zone,
  4. R f(
    1. T arg

The type of a custom Zone.registerUnaryCallback 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 which was passed to the Zone.registerUnaryCallback 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


typedef RegisterUnaryCallbackHandler = ZoneUnaryCallback<R, T> Function<R, T>(
    Zone self, ZoneDelegate parent, Zone zone, R Function(T arg) f);