R RunBinaryHandler(Zone self, ZoneDelegate parent, Zone zone, R f(T1 arg1, T2 arg2), T1 arg1, T2 arg2)

Source 

typedef R RunBinaryHandler<R, T1, T2>(
    Zone self, ZoneDelegate parent, Zone zone,
    R f(T1 arg1, T2 arg2), T1 arg1, T2 arg2);