mandatory      (on|off)    quietly ignore undelivered messages when set to 'off', default is 'on'
durable        (on|off)    persist queue across broker restarts when set to 'on', default is 'off'
no_wait        (on|off)    non-blocking message delivery when set to 'on', default is 'off'
internal       (on|off)    set to 'on' for exchange to be not used directly by publishers, but only when bound to other exchanges