Kombu supports an AMQP URI like amqp://guest:guest@example.org:5672//foobar to use the vhost /foobar.
But, when using pyrabbit's API we have to encode /foobar as %2Ffoobar.
What we could do is only encode it when using the pyrabbit's API and leave the value in the dict as /foobar, but this config is for pyrabbit.