Found this while working with SOLR-7361. This can lead to channel already closed exceptions on a clean close ;(
Commit 1676501 from Mark Miller in branch 'dev/trunk'
[ https://svn.apache.org/r1676501 ]
SOLR-7478: UpdateLog#close shuts down it's executor with interrupts before running it's close logic, possibly preventing a clean close.
Commit 1676506 from Mark Miller in branch 'dev/branches/branch_5x'
[ https://svn.apache.org/r1676506 ]
Bulk close for 5.2.0.