code: function validateNotificationParams(type, params) {
          var validatedParams = null;
  
          params = params || {};
  
          //Don't validate if the formatting is done by the caller
          if (params.format === MESSAGE_FORMAT.LSP) {
              return params;
          }
  
          switch (type) {
              case ToolingInfo.SYNCHRONIZE_EVENTS.DOCUMENT_OPENED:
                  {
                      if (hasValidProps(params, ["filePath", "fileContent", "languageId"])) {
                          validatedParams = params;
                      }
                      break;
                  }
              case ToolingInfo.SYNCHRONIZE_EVENTS.DOCUMENT_CHANGED:
                  {
                      if (hasValidProps(params, ["filePath", "fileContent"])) {
                          validatedParams = params;
                      }
                      break;
                  }
              case ToolingInfo.SYNCHRONIZE_EVENTS.DOCUMENT_SAVED:
                  {
                      if (hasValidProp(params, "filePath")) {
                          validatedParams = params;
                      }
                      break;
                  }
              case ToolingInfo.SYNCHRONIZE_EVENTS.DOCUMENT_CLOSED:
                  {
                      if (hasValidProp(params, "filePath")) {
                          validatedParams = params;
                      }
                      break;
                  }
              case ToolingInfo.SYNCHRONIZE_EVENTS.PROJECT_FOLDERS_CHANGED:
                  {
                      if (hasValidProps(params, ["foldersAdded", "foldersRemoved"])) {
                          validatedParams = params;
                      }
                      break;
                  }
              case ToolingInfo.LANGUAGE_SERVICE.CUSTOM_NOTIFICATION:
                  {
                      validatedParams = params;
                  }
          }
  
          return validatedParams;
      }
docs: /*
  ReponseParams transformer - used by OnNotifications