private function getCacheKey(RequestInterface $request)
    {
        return implode('|', [$request->getIndex(), $request->getType(), $request->getQueryText()]);
    }
private function getCacheKey(RequestInterface $request)
    {
        return implode('|', [$request->getIndex(), $request->getType(), $request->getQueryText()]);
    }
private function getCacheKey ( RequestInterface $ request ) { return implode ( '|' , [ $ request -> getIndex ( ) , $ request -> getType ( ) , $ request -> getQueryText ( ) ] ) ; }
Compute an unique caching key for the spellcheck request.

@param RequestInterface $request Spellchecking request.

@return string
Compute an unique caching key for the spellcheck request .