The type of a custom Zone.runBinary implementation function.
Receives the Zone that the handler was registered on as
a delegate forwarding to the handlers of
self's parent zone as
and the current zone where the error was uncaught as
which will have
self as a parent zone.
f and values
arg2 are the function and arguments
which was passed to the Zone.runBinary of
The default behavior of Zone.runUnary is
f with arguments
arg2 in the current zone,
A custom handler can do things before, after or instead of
The function must only access zone-related functionality through
It should not depend on the current zone (Zone.current).
typedef RunBinaryHandler = R Function<R, T1, T2>(Zone self, ZoneDelegate parent, Zone zone, R Function(T1 arg1, T2 arg2) f, T1 arg1, T2 arg2);