I mean, of course they're slow, it's varargs (on the heap, garbage collected), dynamic function closures (on the heap, garbage collected), and a series of indir

I mean, of course they're slow, it's varargs (on the heap, garbage collected), dynamic function closures (on the heap, garbage collected), and a series of indirect function calls. You really don't need a bunch of benchmarks to tell me it's slow, I believe you. But as much as it pains me, and any premature optimizer, to write "...func(*config)", I don't see the problem unless you find it in a hot section of real code and then do real benchmarks on the code to solve a real problem; these blog post benchmarks are not helpful. I bet regexp.Compile is slow too, but I don't complain about it until I find it in a hot section of code.