code: public function stream_tell()
      {
          if (!$this->handle) {
              return false;
          }
          self::restorePrev();
          $position = \ftell($this->handle);
          self::register();
          return $position;
      }
docs: Retrieve the current position of a stream
  
  @return integer
  
  @see http://php.net/manual/en/streamwrapper.stream-tell.php