runtime proof for pr #10588
base: f88b33a16de988f86782343b348631d11432ddf2
head: ecca86053ca0a5597b9009fcb4c3b80263fce6f0
production manager and command output collection; real scoped subprocesses and disposable http-server children. ssh responses controlled; port reservation held with a deferred. no actual ssh host or remote shell scripts exercised.

PROOF {"version":"main","results":[{"cancellation":"caller","kind":"fresh","stops":0,"settledAtClose":true,"serverAlive":true},{"cancellation":"caller","kind":"reused","stops":0,"settledAtClose":true,"serverAlive":true},{"cancellation":"caller","kind":"external","stops":0,"settledAtClose":true,"serverAlive":true},{"cancellation":"manager","kind":"fresh","stops":0,"settledAtClose":false,"serverAlive":true},{"cancellation":"manager","kind":"reused","stops":0,"settledAtClose":false,"serverAlive":true},{"cancellation":"manager","kind":"external","stops":0,"settledAtClose":false,"serverAlive":true}]}
PROOF {"version":"fixed","results":[{"cancellation":"caller","kind":"fresh","stops":1,"settledAtClose":true,"serverAlive":false},{"cancellation":"caller","kind":"reused","stops":0,"settledAtClose":true,"serverAlive":true},{"cancellation":"caller","kind":"external","stops":0,"settledAtClose":true,"serverAlive":true},{"cancellation":"manager","kind":"fresh","stops":1,"settledAtClose":true,"serverAlive":false},{"cancellation":"manager","kind":"reused","stops":0,"settledAtClose":true,"serverAlive":true},{"cancellation":"manager","kind":"external","stops":0,"settledAtClose":true,"serverAlive":true}]}