ThrottledPublishingAgent:answers sometimes contains one or more old posts

[brohitbrose]

First entry in the below output should have been expired ~2 weeks ago. It appears that underlying SubmissionAgent did clean up its state.

% swim-cli sync -h warps://munin.swim.services -n /throttledPublish -l answers
@update(key:"/submission/y96brn")
@update(key:"/submission/yj8ggc")@answer{taxa:{shicow},reviewers:{brohitbrose}}
@update(key:"/submission/yj950p")@answer{taxa:{rinphe1},reviewers:{pooter_birdman}}
@update(key:"/submission/yj9o8x")
@update(key:"/submission/yj9y2m")@answer{taxa:{brnnod},reviewers:{kiwikiu}}

[brohitbrose]

This is a direct result of https://github.com/swimos/swim/issues/110.