init: Fixes for file descriptor accounting

[Empact]

This rebases and revises #16003 for clarity of review.

Aims to fix #18911.

[DrahtBot]

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Reviews

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Type	Reviewers
Concept ACK	fjahr, TheCharlatan

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #29415 (Broadcast own transactions only via short-lived Tor or I2P connections by vasild)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

[fjahr]

Concept ACK

I think it would be very helpful to add comments to explain what is going on. See my accidentally duplicate PR for some suggestions: #27730.

[fjahr]

Needs an explanation of why it is ok to take FD_SETSIZE completely out of the equation in the commit description.

[TheCharlatan]

Concept ACK

First three commits look good, but the last one needs more descriptions and comments as mentioned by fjahr.

[DrahtBot]

🤔 There hasn't been much activity lately and the CI seems to be failing.

If no one reviewed the current pull request by commit hash, a rebase can be considered. While the CI failure may be a false positive, the CI hasn't been running for some time, so there may be a real issue hiding as well. A rebase triggers the latest CI and makes sure that no silent merge conflicts have snuck in.

[TheCharlatan]

This was rebased fairly recently, but you have not addressed this open comment #27539 (comment) . Are you still working on this?