Zend\Mail\Storage\Mbox::getUniqueId
get unique id for one or all messages
Mbox does not support unique ids (yet) - it's always the same as the message number. That shouldn't be a problem, because we can't change mbox files. Therefor the message number is save enough.
Signature
public function getUniqueId([int|null
$id = null] )
Parameters
$id
— object- message number
Returns
- array|string
- message number for given message or all messages as array