docs: def _get_postqueue_stats(self, postfix_config_dir, tags):
  
          # get some intersting configuratin values from postconf
          pc_output, _, _ = get_subprocess_output(['postconf', 'mail_version'], self.log, False)
          postfix_version = pc_output.strip('\n').split('=')[1].strip()
          pc_output, _, _ = get_subprocess_output(['postconf', 'authorized_mailq_users'], self.log, False)
          authorized_mailq_users = pc_output.strip('\n').split('=')[1].strip()
  
          self.log.debug('authorized_mailq_users : {}'.format(authorized_mailq_users))
  
          output, _, _ = get_subprocess_output(['postqueue', '-c', postfix_config_dir, '-p'], self.log, False)
  
          active_count = 0
          hold_count = 0
          deferred_count = 0
  
          # postque -p sample output
          '''
          root@postfix:/opt/datadog-agent/agent/checks.d# postqueue -p
          ----Queue ID----- --Size-- ---Arrival Time---- --Sender/Recipient------
          3xWyLP6Nmfz23fk        367 Tue Aug 15 16:17:33 root@postfix.devnull.home
                                                              (deferred transport)
                                                              alice@crypto.io
  
          3xWyD86NwZz23ff!       358 Tue Aug 15 16:12:08 root@postfix.devnull.home
                                                              (deferred transport)
                                                              bob@crypto.io
  
          -- 1 Kbytes in 2 Requests.
          '''
  
          for line in output.splitlines():
              if '*' in line:
                  active_count += 1
                  continue
              if '!' in line:
                  hold_count += 1
                  continue
              if line[0:1].isdigit():
                  deferred_count += 1
  
          self.log.debug('Postfix Version: %s' % postfix_version)
  
          self.gauge(
              'postfix.queue.size', active_count, tags=tags + ['queue:active', 'instance:{}'.format(postfix_config_dir)]
          )
          self.gauge(
              'postfix.queue.size', hold_count, tags=tags + ['queue:hold', 'instance:{}'.format(postfix_config_dir)]
          )
          self.gauge(
              'postfix.queue.size',
              deferred_count,
              tags=tags + ['queue:deferred', 'instance:{}'.format(postfix_config_dir)],
          )