code: func (m *model) Connection(deviceID protocol.DeviceID) (connections.Connection, bool) {
  	m.pmut.RLock()
  	cn, ok := m.conn[deviceID]
  	m.pmut.RUnlock()
  	if ok {
  		m.deviceWasSeen(deviceID)
  	}
  	return cn, ok
  }
docs: // Connection returns the current connection for device, and a boolean whether a connection was found.