return
	}
	p.readFn = fn
	if dst == &p.breakErr {
		if p.b != nil {
			p.unread += p.b.Len()
		}
		p.b = nil
	}
	*dst = err
	p.closeDoneLocked()
}

// requires p.mu be held.
func (p *http2pipe) closeDoneLocked() {
	if p.donec == nil {
		return
	}
	// Close if unclosed. This isn't racy since we always
	// hold p.mu while closing.
	select {
	case <-p.donec: