Detect UDS client disconnection

## Feature Request

### Motivation

We have a UDS server that looks for DHCP leases for a client. When the client disconnects we would like to be able to recognize this and stop DORA on the server side - otherwise the server just keeps searching for a lease. It would be useful in this case to recognize that the client disconnected and that we can do clean up on the server side.

I understand this issue has been talked about before in issue number #377, however, that was related to streamed connections.

### Proposal

Im unsure of how this would be implemented. I do think having some sort of channel which sends messages about disconnected clients which would give specific information on which client disconnected would be helpful.