Comment 6 for bug 956132

IIRC, after an exception any operation on the channel will fail, since the server considers it closed.
If you don't send too many messages, doing a no-op call like declaring an existing exchange can indeed be a good way to check.
Unfortunately, that's not my use case, my application sends several hundreds of messages per second, so checking each one in this manner would cause too much overhead.
But thanks for helping.