Seeing this warning while investigating another issue:
This happens when the IOException is thrown while attempting to write the initial OPTIONS query on a new connection.
I suspect it's some sort of indirect recursion into InflightHandler.abortAllInFlight. We might want to go back to copying inFlight, clearing it, and iterating the copy like it was done before.
It is indeed InflightHandler.abortAllInFlight.
The first error fails the OPTIONS query with ConnectInitHandler.setConnectFailure. That method calls ctx.channel().close(), which causes another error "Lost connection to remote peer" to be fired on the pipeline.