Optionalarg1: ValueFirst argument that is passed from caller.
Optionalarg2: ValueSecond argument that is passed from caller.
Optionalarg3: ValueThird argument that is passed from caller.
Optionalarg4: ValueFourth argument that is passed from caller.
Optionalarg5: ValueFifth argument that is passed from caller.
Optionalarg6: ValueSixth argument that is passed from caller.
Optionalarg7: ValueSeventh argument that is passed from caller.
Optionalarg8: ValueEighth argument that is passed from caller.
Callback used by Events and EventHandle functions. Note the callback is limited to 8 arguments.