public function header($name, $default = NULL) {
    if (isset($this->headers[$name])) {
      return $this->headers[$name];
    }
    return $default;
  }
public function header($name, $default = NULL) {
    if (isset($this->headers[$name])) {
      return $this->headers[$name];
    }
    return $default;
  }
public function header ( $ name , $ default = NULL ) { if ( isset ( $ this -> headers [ $ name ] ) ) { return $ this -> headers [ $ name ] ; } return $ default ; }
Convenience function to retrieve a single header.

@param string $name
The name of the header.
@param mixed $default
An optional default value.

@retval mixed
@return mixed
The value, if found, or the default, is specified, or NULL.
Convenience function to retrieve a single header .