[idea] Summarize connected peers

[harold]

It would be neat if this library could summarize the connected peers.

This could be repl-only functionality, or perhaps also presented as a web page.

One could query the peer library to know how many peers are connected and what RPC, subscriptions, and events each peer is participating in. Dangling connections and associated resources are always going to be a concern with a library like this (esp. in 'real' or at-scale use).