Youshido\GraphQL\Execution\Request::getQueryVariables PHP Method

    public function getQueryVariables()
    {
        return $this->queryVariables;
    }

 private function assertAllVariablesUsed(Request $request)
 {
     foreach ($request->getQueryVariables() as $queryVariable) {
         if (!$queryVariable->isUsed()) {
             throw new InvalidRequestException(sprintf('Variable "%s" not used', $queryVariable->getName()), $queryVariable->getLocation());
         }
     }
 }