code: func Aftertouch(channel, key, vel int) *Event {
  	return &Event{
  		MsgChan:  uint8(channel),
  		MsgType:  uint8(EventByteMap["AfterTouch"]),
  		Note:     uint8(key),
  		Velocity: uint8(vel),
  	}
  }
docs: // AfterTouch returns a pointer to a new aftertouch event