public function setEtag($etag, $weak = false): void
    {
        $etag = trim($etag, '"');
        $this->response->setHeader('ETag', (true === $weak ? 'W/' : '') . '"' . $etag . '"');
    }
public function setEtag($etag, $weak = false): void
    {
        $etag = trim($etag, '"');
        $this->response->setHeader('ETag', (true === $weak ? 'W/' : '') . '"' . $etag . '"');
    }
public function setEtag ( $ etag , $ weak = false ) : void { $ etag = trim ( $ etag , '"' ) ; $ this -> response -> setHeader ( 'ETag' , ( true === $ weak ? 'W/' : '' ) . '"' . $ etag . '"' ) ; }
Sets the ETag value

@param  string $etag The ETag unique identifier
@param  bool   $weak Whether you want a weak ETag or not

@return void
Sets the ETag value