code: def thread(self):
          
          if not self._thread_calculated:
              self._thread_calculated = True
  
              split_tokens = self.split_tokens
  
              if not self.datetime_nextpos:
                  return None
              if len(split_tokens) <= self.datetime_nextpos:
                  return None
  
              connection_token = split_tokens[self.datetime_nextpos]
              match = re.match(r'^\[([^\]]*)\]$', connection_token)
              if match:
                  self._thread = match.group(1)
  
              if self._thread is not None:
                  if self._thread in ['initandlisten', 'mongosMain']:
                      if len(split_tokens) >= 5 and split_tokens[-5][0] == '#':
                          self._conn = 'conn' + split_tokens[-5][1:]
                  elif self._thread.startswith('conn'):
                      self._conn = self._thread
          return self._thread
docs: Extract thread name if available (lazy).