title: CoAP confirmable response
body: <p>My server exposes a set of measurements but only those that have not been read yet.  For this purpose, I have only implemented a single resource  <code>/new</code> that discards measurements that it has just sent after a <code>GET</code> request.  How can I make the server wait for the requester to acknowledge the reception of the response?</p>
  
  <p>I know this is not fully respectful of CoAP semantics but it would still be useful for me.  I mean the server would only discard readings that have actually been received by some client.</p>