When we have seen the truth that having a birth, having a body is suffering. Why not simply drop all the attachments, stop sustaining the body and pass away to parinibbana, what is the point of sustaining in samsara and holding on to body ?
I dont think this will count as suicide.
If you say that this is attachment to non-being then yes it is, if you do not have nibbana in your mind as a goal then it cannot happen and otherwise there will be rebirth.
Buddha himself said - keep your mind at nibbana.
Buddha himself took Mahaparinibbana.