Dispatcher to handle anon func returned in closure

[dfava]

Take this higher order function that returns an anonymous function:

func ReturnAnonFunc(component string) func(string, float64) {
	return func(label string, time float64) {
		TestFunctionsCalled[fmt.Sprintf("ReturnAnonFunc.%s", component)] = true
	}
}

We can now register with dispatcher like so:

	ctx = querysql.WithDispatcher(ctx, querysql.GoMSSQLDispatcher([]interface{}{
		testhelper.ReturnAnonFunc("myComponent"),
	}))

That's because the anon function is named in go as ReturnAnonFunc.func1. So, we can use the ReturnAnonFunc part of the anonymous function name in order to dispatch the correct function at runtime.

This means we can have one anonymous function per high-order function. Meaning, the dispatcher cannot disambiguate between:

testhelper.ReturnAnonFunc("myComponent"),
testhelper.ReturnAnonFunc("myComponent2"),

Therefore, if the user tries to record more than one anon functions from the same higher-order function, the dispatcher will panic.