Prevents the client from accidentally connecting to a server on a
different network.
I noticed its possible to connect to mainnet servers on a signet
instance causing the recent peers to get populated with mainnet peers
rendering the wallet instance barely usable. Doing this check should
prevent this and similar issues.
Often when the wallet creates a tx, the flow is:
- create unsigned tx
- sign tx
- broadcast tx, but don't save it in history
- server sends notification that status of a subscribed address changed
- client calls scripthash.get_history
- client sees txid in scripthash.get_history response
- client calls blockchain.transaction.get to request missing tx
Instead, now when we broadcast a tx on an interface, we cache that tx *for that interface*,
and just before calling blockchain.transaction.get, we lookup in the cache.
Hence this will often save a network request.
