`Acceptor::readCallback` fatal errors

A backend running on Drogon for 19 hours started not responding to any requests, checking the console logs I can see this:
```sh
20240827 13:14:10.048660 UTC 93159 FATAL Too many open files (errno=24) Accpetor::readCallback - Acceptor.cc:86
```

Reading the code of `Acceptor`, it seems it is unable to read from the socket?

After restarting the Drogon backend, it went back to normal.