Return Mandrill API response to the caller

Calling drupal_mail() doesn't return Mandrill API response in any form. It just returns $ret['result'] = TRUE.
It is desirable to receive Mandrill response instead of just TRUE, to get message _id
Example call:

$ret = drupal_mail('my_module', 'my_key', $to, $lang, $params, $from);

Example of Mandril API response:

  $ret['result'] = Array
    (
        [0] => Array
            (
                [email] => recipient.email@example.com
                [status] => sent
                [reject_reason] => hard-bounce
                [_id] => abc123abc123abc123abc123abc123
            )
    
    )