Cannot read property 'host' of undefined

[Analect]

@pelger
In our usage of microbial, I think we're experiencing the same problem as described here:
rjrodger/seneca-kafka-transport#1
There, you recommend running deregister.js to clear out slots in zookeeper, although that solution seems to be seneca-kafka-transport specific ...
Is there any other way for microbial to directly flush out zookeeper that might help us resolve?
Thanks.
Colum

error: uncaughtException: Cannot read property 'host' of undefined
error: TypeError: Cannot read property 'host' of undefined
at _makeBrokerKey (/home/me/Development/Tools/Eolas/eolas/node_modules/microbial/node_modules/kafkaesque/lib/kafkaesque.js:48:18)
at /home/me/Development/Tools/Eolas/eolas/node_modules/microbial/node_modules/kafkaesque/lib/kafkaesque.js:121:23
at Object.callback (/home/me/Development/Tools/Eolas/eolas/node_modules/microbial/node_modules/kafkaesque/lib/kafkaesque.js:56:85)
at Socket. (/home/me/Development/Tools/Eolas/eolas/node_modules/microbial/node_modules/kafkaesque/lib/api.js:246:17)
at Socket.emit (events.js:95:17)
at Socket. (stream_readable.js:764:14)
at Socket.emit (events.js:92:17)
at emitReadable (_stream_readable.js:426:10)
at emitReadable (_stream_readable.js:422:5)
at readableAddChunk (_stream_readable.js:165:9)
mccoole@ubuntu:~/Development/Tools/Eolas/eolas/services$