From what I understand of AMQP, "clients" of the message bus can use any format they wish i.e. the fabric is opaque to the client messages.
Is it a common practice to include an overhead specifying the protocol format of the messages for a given "exchange"? e.g. have a "\n" terminated first line specifying the protocol MIME-type (XML, JSON etc.)
Or is there a configuration option I haven't stumbled upon yet?