This separates the socket event collection logic from the logic
deciding which events we're interested in at all.
Partial backport of Core [[https://github.com/bitcoin/bitcoin/pull/14336 | PR14336]]
https://github.com/bitcoin/bitcoin/pull/14336/commits/7e403c0ae705455aa66f7df9a9a99f462fd4e9a8
Depends on D6459