// numbers of args.
func makeArgSlices(size int) (argVals []Value, argRefs []ref) {
	// value chosen for being power of two, and enough to handle all web APIs
	// in particular, note that WebGL2's texImage2D takes up to 10 arguments
	const maxStackArgs = 16
	if size <= maxStackArgs {
		// as long as makeArgs is inlined, these will be stack-allocated
		argVals = make([]Value, size, maxStackArgs)