Hunting Memory Leaks in bsnmpd with DTrace

One of my FreeBSD boxes runs bsnmpd, the base system SNMP daemon.
The machine is on 15.0-p2, and the daemon kept growing until the kernel ran out of patience and OOM-killed it.
That is not a good feature for a daemon.

I could have just added a cron job to restart it and called it a day.
But a leak that kills a long-running daemon is exactly the kind of thing I like to chase, and I already had a tool for it.