=== load rig (dfveto0 detachable, dfveto1 vetoes; dfleak driver) ===
		327 nexus/dfleak
		328 nexus/dfveto
dev.dfveto.0.%desc: DF-5789 half-unload rig
dev.dfveto.1.%desc: DF-5789 half-unload rig

=== vmstat -m bus row BEFORE the failed unload ===

                bus   1.11K   1.66M       0    390M    9.07K

=== kldunload #1: unit1 veto expected AFTER unit0 was killed ===
kldunload: can't unload file: Device busy
KLDUNLOAD-1 FAILED as predicted: 1

=== aftermath ===
-- dev.dfveto tree (dfveto0 subtree must be GONE):
dev.dfveto.1.%desc: DF-5789 half-unload rig
dev.dfveto.1.%driver: dfveto
dev.dfveto.1.%parent: nexus0
-- zombie as seen by an unprivileged user (walker):
generation 18320 (version 1)
[110] dfveto0      drv=           state=NOTPRESENT  parent=0xfffff8008bb7f800
total listed (capped 4096): 112; ZOMBIES (no driver, state<ATTACHED): 62
-- in-kernel status via sysctl read:
hw.df5789.cooperate: 0

=== kldunload #2: wedge is permanent for unit1 ===
kldunload: can't unload file: Device busy
KLDUNLOAD-2 FAILED as predicted: 1

=== cooperate and unload cleanly (dfveto0 stays dead forever) ===
hw.df5789.cooperate: 0 -> 1
unloaded: dfveto1 detached; dfveto0 was skipped (driver==NULL)
-- zombie STILL in tree after unload:
[110] dfveto0      drv=           state=NOTPRESENT  parent=0xfffff8008bb7f800
[111] dfveto1      drv=           state=NOTPRESENT  parent=0xfffff8008bb7f800
total listed (capped 4096): 112; ZOMBIES (no driver, state<ATTACHED): 63
module gone