}
	if !m.respMu.TryLock() {
		// Cancel before locking - will unblock any pending sends.
		if m.cancelFn != nil {
			m.cancelFn(context.Canceled)
		}
		// Wait for senders to release.
		m.respMu.Lock()
	}

	defer m.respMu.Unlock()
	m.closeLocked()
}

func (m *muxClient) closeLocked() {
	if m.closed {
		return
	}