Feature Request: Add onClose handler for custom logic when a socket is closed/disconnected

[titanism]

No description provided.

[titanism]

This would need implemented for IMAP/POP3. Right now the only way (other than adding custom listeners) is to modify IMAP notifier logic, specifically releaseConnection function.

[titanism]

Bumping this request, as there's no current way to prevent connection overflow.

For example, any user can spawn 10000+ connections to a server and there is no application-layer functionality that can prevent this (other than if you were to write a loop or something on the IMAP/POP3 server instances and iterate over this.connections, which seems like an anti-pattern as opposed to using onConnect and onClose like we have in smtp-server).