func _Ranger[Elem any]() (*_Sender[Elem], *_Receiver[Elem]) {
	c := make(chan Elem)
	d := make(chan struct{})
	s := &_Sender[Elem]{
		values: c,
		done:   d,
	}
	r := &_Receiver[Elem]{
		values: c,
		done:   d,
	}
	runtime.SetFinalizer(r, (*_Receiver[Elem]).finalize)
	return s, r
}

// A _Sender is used to send values to a Receiver.
type _Sender[Elem any] struct {
	values chan<- Elem

func _Ranger[Elem any]() (*_Sender[Elem], *_Receiver[Elem]) {
	c := make(chan Elem)
	d := make(chan struct{})
	s := &_Sender[Elem]{
		values: c,
		done:   d,
	}
	r := &_Receiver[Elem]{
		values: c,
		done:   d,
	}
	runtime.SetFinalizer(r, (*_Receiver[Elem]).finalize)
	return s, r
}

// A _Sender is used to send values to a Receiver.
type _Sender[Elem any] struct {
	values chan<- Elem

John Howard <******@****.***> 1655951219 -0700

carlory <******@****.***> 1714102710 +0800

func Ranger[T any]() (*Sender[T], *Receiver[T]) {
	c := make(chan T)
	d := make(chan bool)
	s := &Sender[T]{values: c, done: d}
	r := &Receiver[T]{values: c, done: d}
	runtime.SetFinalizer(r, r.finalize)
	return s, r
}

// A sender is used to send values to a Receiver.
type Sender[T any] struct {
	values chan<- T
	done <-chan bool
}

// Send sends a value to the receiver. It returns whether any more

// the receiver stops reading them.
func Ranger[T any]() (*Sender[T], *Receiver[T]) {
	c := make(chan T)
	d := make(chan bool)
	s := &Sender[T]{values: c, done: d}
	r := &Receiver[T]{values: c, done: d}
	runtime.SetFinalizer(r, r.finalize)
	return s, r
}

// A sender is used to send values to a Receiver.
type Sender[T any] struct {
	values chan<- T
	done   <-chan bool
}

func Ranger[Elem any]() (*Sender[Elem], *Receiver[Elem]) {
	c := make(chan Elem)
	d := make(chan struct{})
	s := &Sender[Elem]{
		values: c,
		done:   d,
	}
	r := &Receiver[Elem]{
		values: c,
		done:   d,
	}
	runtime.SetFinalizer(r, (*Receiver[Elem]).finalize)
	return s, r
}

// A Sender is used to send values to a Receiver.
type Sender[Elem any] struct {
	values chan<- Elem

func Ranger[Elem any]() (*Sender[Elem], *Receiver[Elem]) {
	c := make(chan Elem)
	d := make(chan struct{})
	s := &Sender[Elem]{
		values: c,
		done:   d,
	}
	r := &Receiver[Elem]{
		values: c,
		done:   d,
	}
	runtime.SetFinalizer(r, (*Receiver[Elem]).finalize)
	return s, r
}

// A Sender is used to send values to a Receiver.
type Sender[Elem any] struct {
	values chan<- Elem

func (m *Map[K, V]) InOrder() *Iterator[K, V] {
	sender, receiver := chans_Ranger[keyValue[K, V]]()
	var f func(*node[K, V]) bool
	f = func(n *node[K, V]) bool {
		if n == nil {
			return true
		}
		// Stop sending values if sender.Send returns false,
		// meaning that nothing is listening at the receiver end.
		return f(n.left) &&
			sender.Send(keyValue[K, V]{n.key, n.val}) &&
			f(n.right)
	}
	go func() {

func (m *Map[K, V]) InOrder() *Iterator[K, V] {
	sender, receiver := chans_Ranger[keyValue[K, V]]()
	var f func(*node[K, V]) bool
	f = func(n *node[K, V]) bool {
		if n == nil {
			return true
		}
		// Stop sending values if sender.Send returns false,
		// meaning that nothing is listening at the receiver end.
		return f(n.left) &&
                        sender.Send(keyValue[K, V]{n.key, n.val}) &&
			f(n.right)
	}