code: @Override
      protected void registerRequest(RestRequestValidator requestValidator,
                                     ChannelHandlerContext ctx,
                                     MessageEvent messageEvent) {
  
          // At this point we know the request is valid and we have a
          // error handler. So we construct the composite Voldemort
          // request object.
          CompositeVoldemortRequest<ByteArray, byte[]> requestObject = requestValidator.constructCompositeVoldemortRequestObject();
  
          if(requestObject != null) {
  
              DynamicTimeoutStoreClient<ByteArray, byte[]> storeClient = null;
  
              if(!requestValidator.getStoreName().equalsIgnoreCase(RestMessageHeaders.SCHEMATA_STORE)) {
  
                  storeClient = this.fatClientMap.get(requestValidator.getStoreName());
                  if(storeClient == null) {
                      logger.error("Error when getting store. Non Existing store client.");
                      RestErrorHandler.writeErrorResponse(messageEvent,
                                                          HttpResponseStatus.BAD_REQUEST,
                                                          "Non Existing store client. Critical error.");
                      return;
                  }
              } else {
                  requestObject.setOperationType(VoldemortOpCode.GET_METADATA_OP_CODE);
              }
  
              CoordinatorStoreClientRequest coordinatorRequest = new CoordinatorStoreClientRequest(requestObject,
                                                                                                   storeClient);
              Channels.fireMessageReceived(ctx, coordinatorRequest);
  
          }
      }
docs: Constructs a valid request and passes it on to the next handler. It also
  creates the 'StoreClient' object corresponding to the store name
  specified in the REST request.
  
  @param requestValidator The Validator object used to construct the
  request object
  @param ctx Context of the Netty channel
  @param messageEvent Message Event used to write the response / exception