quorum connection manager shutdown takes long time

Hi,

I'm using ZooKeeper 3.4.5 (over IPSec!), and I saw a case where the
quorum connection manager takes a long time to shut down. It looks
like one of the receiver threads didn't exit for ~14 minutes.

https://paste.apache.org/2wFN?action=download

The tickTime is set to 3000 and initLimit is set to 5, so readInt()
should have gotten a socket timeout exception after 15 seconds.
Instead, it got an eof exception after 14 minutes. I didn't get a
chance to do a thread dump when this happened, but has anybody seen
something similiar?