RunUnaryHandler#
The type of a custom Zone.runUnary implementation function.
A function used as ZoneSpecification.runUnary to specialize the behavior of a new zone.
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 and value arg are the function and argument
which was passed to the Zone.runUnary
of zone.
The default behavior of Zone.runUnary
is
to call f with argument arg in the current zone, zone.
A custom handler can do things before, after or instead of
calling f.
The function must only access zone-related functionality through
self, parent or zone.
It should not depend on the current zone (Zone.current).