uv_poll_stop: Assertion `!uv__is_closing(handle)' failed.

[aphyr]

With redis f88f866 and redisraft 2d1cf30, testing with membership changes, node pauses, crashes, and partitions, occasionally nodes crash with the following assertion:

76761:09 May 10:22:10.877 <raftlib> received entry t:59 id: 580797296 idx: 4067
76761:09 May 10:22:10.882 node:590852739: raft.c:479: <raftlib> sending appendentries: ci:4067 comi:4066 t:59 lc:4066 pli:4066 plt:59 msgid:79 #1
76761:09 May 10:22:10.882 node:590852739: node.c:361: NodeAddPendingResponse: id=1126, type=raft, request_time=1589044930882
76761:09 May 10:22:10.882 node:98688395: raft.c:479: <raftlib> sending appendentries: ci:4067 comi:4066 t:59 lc:4066 pli:4066 plt:59 msgid:79 #1
76761:09 May 10:22:10.882 node:98688395: node.c:361: NodeAddPendingResponse: id=1127, type=raft, request_time=1589044930882
76761:09 May 10:22:10.882 node:1029979987: node.c:74: Node connection established.
redis-server: src/unix/poll.c:112: uv_poll_stop: Assertion `!uv__is_closing(handle)' failed.

This error looks recoverable; a subsequent restart went OK, and the rest of the cluster kept serving requests.

20200509T131903.000-0400.zip

To reproduce, use Jepsen.redis 6c063da0503e9430a0354d37da8a4da430d1671e, and run:

lein run test-all --raft-version 2d1cf30 --time-limit 600 --nemesis partition,kill,pause,member --follower-proxy --test-count 16 --concurrency 4n

[aphyr]

This looks resolved as of e0123a9.