Missing metrics about the RTR clients

[netixx]

Hello,

I would like to get metrics about the RTR clients that are connected to a given instance.

For example:

• the number of clients currently connected
• the last time a VRP was sent to the client (by client IP, VRP afi)
• the count of VRP sent to each client (by client IP, VRP afi)

These are just ideas (depending on what is implemented, some are redundant) :)

Currently I only see metrics related to the upstream part, but none related to the downstream part.

[partim]

Thank you for the suggestion! This seems like a very useful addition, indeed.

[netixx]

If you need someone to test a branch or test release, I am available.
Sorry I cannot help on the code, I don't know rust... yet :)

[partim]

I just realised that #115 doesn’t include metrics of the current serial number of the unit or the number of VRPs, which we should probably add. So I’ll re-open the issue.