My view of what ideal 'LVQ' behaviour would be like is that the 'queue'
would really be more like a 'topic' where the last message for each key was
always saved. Clients would subscribe to it and receive the last message
published for each key and subsequently any updates (i.e. any new messages). I.e. the consumers are always non-competing.
Rob Godfrey also points out that if subscribers fall behind they need only be sent the latest for every key (i.e. any superceded values can be skipped).