code: public static void putAppConfig(String appName, FaultToleranceConfig value) {
          if (appName == null) {
              if (LOGGER.isWarnEnabled()) {
                  LOGGER.warn("App name is null when put fault-tolerance config");
              }
              return;
          }
          if (value != null) {
              APP_CONFIGS.put(appName, value);
              if (LOGGER.isInfoEnabled(appName)) {
                  LOGGER.infoWithApp(appName, "Get a new resource, value[" + value + "]");
              }
          } else {
              APP_CONFIGS.remove(appName);
              if (LOGGER.isInfoEnabled(appName)) {
                  LOGGER.infoWithApp(appName, "Remove a resource, key[" + appName + "]");
              }
          }
          calcEnable();
      }
docs: Put app config.
  
  @param appName the app name
  @param value   the value