func Exit(code int) {
	for i := len(atExitFuncs) - 1; i >= 0; i-- {
		f := atExitFuncs[i]
		atExitFuncs = atExitFuncs[:i]
		f()
	}
	os.Exit(code)
}

// To enable tracing support (-t flag), set EnableTrace to true.
const EnableTrace = false

// forEachGC calls fn each GC cycle until it returns false.
func forEachGC(fn func() bool) {
	type T [32]byte // large enough to avoid runtime's tiny object allocator

	var finalizer func(*T)