code: func (b *Driver) Emergency() (err error) {
  	b.stepsfa0b++
  	buf := []byte{0x02, byte(b.stepsfa0b) & 0xff, 0x02, 0x00, 0x04, 0x00}
  	err = b.adaptor().WriteCharacteristic(priorityCharacteristic, buf)
  
  	return err
  }
docs: // Emergency sets the Minidrone into emergency mode