stream-events gets stuck

ssh codereview.qt-project.org gerrit stream-events
just got stuck, both existing and new connections.

show-queue has some entries like

2895a744                       com.google.gerrit.sshd.commands.StreamEvents$3@7

and many more like

2283a41c waiting ....          com.google.gerrit.sshd.commands.StreamEvents$3@4

the error log doesn't mention anything.

unsurprisingly, a restart "cured" the issue (for the time being ...).

as a possible trigger, there was a huge push (~150 commits) which might have blown gerrit's little mind ...