Support Rust listeners on C LegacyFiles

[stevenengler]

This should allow us to add rust state/status listener callback closures to LegacyFiles in the future. This means that we can write rust objects that add listeners to LegacyFiles. For example, we can write a rust epoll file object that listens for events on C TCP or RegularFile objects using rust closures.

[codecov]

Codecov Report

Base: 67.03% // Head: 67.85% // Increases project coverage by +0.82% 🎉

Coverage data is based on head (7aa8f26) compared to base (6064cc8).
Patch coverage: 95.00% of modified lines in pull request are covered.

❗ Current head 7aa8f26 differs from pull request most recent head e2543c9. Consider uploading reports for the commit e2543c9 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2715      +/-   ##
==========================================
+ Coverage   67.03%   67.85%   +0.82%     
==========================================
  Files         203      203              
  Lines       30513    30507       -6     
  Branches     5970     5963       -7     
==========================================
+ Hits        20454    20701     +247     
+ Misses       5375     5113     -262     
- Partials     4684     4693       +9     

Flag	Coverage Δ
tests	67.85% <95.00%> (+0.82%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/main/utility/legacy_callback_queue.rs	85.71% <93.75%> (+6.08%)	⬆️
src/main/host/descriptor/mod.rs	69.18% <95.83%> (+2.11%)	⬆️
src/main/host/descriptor/socket/inet/mod.rs	27.34% <0.00%> (-15.97%)	⬇️
src/main/host/descriptor/socket/inet/tcp.rs	67.02% <0.00%> (-3.25%)	⬇️
src/lib/shmem/src/scmutex.rs	87.05% <0.00%> (-2.36%)	⬇️
src/main/host/network_interface.rs	91.37% <0.00%> (-0.43%)	⬇️
src/main/network/net_namespace.rs	77.98% <0.00%> (-0.40%)	⬇️
src/main/utility/byte_queue.rs	56.01% <0.00%> (ø)
src/test/signal/test_signals.rs	84.64% <0.00%> (+0.35%)	⬆️
src/main/core/manager.rs	63.63% <0.00%> (+0.44%)	⬆️
... and 25 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[stevenengler]

Runtime performance and memory usage seems to be slightly worse in a tor benchmark. I'm not sure why the memory usage appears worse. The simulation network results did not change.

https://github.com/shadow/benchmark-results/tree/master/tor/2023-02-07-T20-06-50