final protected function next(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface {
        if ($this->_next) {
            return $this->_next->process($request, $handler);
        }
        return $handler->handle($request);
    }
final protected function next(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface {
        if ($this->_next) {
            return $this->_next->process($request, $handler);
        }
        return $handler->handle($request);
    }
final protected function next ( ServerRequestInterface $ request , RequestHandlerInterface $ handler ) : ResponseInterface { if ( $ this -> _next ) { return $ this -> _next -> process ( $ request , $ handler ) ; } return $ handler -> handle ( $ request ) ; }
Pass request to the next middleware. If there are no next middleware,
it will pass the request to the handler
@param  ServerRequestInterface  $request
@param  RequestHandlerInterface $handler
@return ResponseInterface
Pass request to the next middleware . If there are no next middleware it will pass the request to the handler