func valueMethodName() string {
	var pc [5]uintptr
	n := runtime.Callers(1, pc[:])
	frames := runtime.CallersFrames(pc[:n])
	var frame runtime.Frame
	for more := true; more; {
		const prefix = "reflect.Value."
		frame, more = frames.Next()
		name := frame.Function
		if len(name) > len(prefix) && name[:len(prefix)] == prefix {
			methodName := name[len(prefix):]

// The purpose of this function is to provide more helpful error messages.
func relevantCaller() runtime.Frame {
	pc := make([]uintptr, 16)
	n := runtime.Callers(1, pc)
	frames := runtime.CallersFrames(pc[:n])
	var frame runtime.Frame
	for {
		frame, more := frames.Next()
		if !strings.HasPrefix(frame.Function, "net/http.") {
			return frame
		}
		if !more {
			break
		}
	}
	return frame
}

	// defer inline frame expansion until the profile is reported.
	// The "maxSkip" term is for frame pointer unwinding, where we
	// want to end up with debug.profstackdebth frames but will discard
	// some "physical" frames to account for skipping.
	return make([]uintptr, 1+maxSkip+debug.profstackdepth)
}

// makeProfStack returns a buffer large enough to hold a maximum-sized stack
// trace.