public function has($name)
    {
        return isset($this->headers[$name]) || array_key_exists($name, $this->headers);
    }
public function has($name)
    {
        return isset($this->headers[$name]) || array_key_exists($name, $this->headers);
    }
public function has ( $ name ) { return isset ( $ this -> headers [ $ name ] ) || array_key_exists ( $ name , $ this -> headers ) ; }
Determine if a header exists with a specific key.

@param string $name

@return boolean
Determine if a header exists with a specific key .