@Override
      public Object set(Map<String, Object> location, String target, MultipartFile multipartFile) {
         return location.put(target, multipartFile);
      }
Mapper for handling populating the query variables with the files specified by object paths
in the multi-part request.
graphql-protocol/src/main/java/com/linecorp/armeria/server/graphql/protocol/MultipartVariableMapper.java