code: public function setHostInfo($value)
      {
          $this->_hostName = null;
          $this->_hostInfo = $value === null ? null : rtrim($value, '/');
      }
docs: Sets the schema and host part of the application URL.
  This setter is provided in case the schema and hostname cannot be determined
  on certain Web servers.
  @param string|null $value the schema and host part of the application URL. The trailing slashes will be removed.
  @see getHostInfo() for security related notes on this property.