public function headerExists(string $header): bool
    {
        return array_key_exists(self::processKey($header), $this->getHeaders());
    }
public function headerExists(string $header): bool
    {
        return array_key_exists(self::processKey($header), $this->getHeaders());
    }
public function headerExists ( string $ header ) : bool { return array_key_exists ( self :: processKey ( $ header ) , $ this -> getHeaders ( ) ) ; }
Returns true if headers exists, false otherwise

@param string $header

@return bool
Returns true if headers exists false otherwise