docs: @Nullable
    public static String getHealthCheckedServiceName(@Nullable Map<String, ?> serviceConfig) {
      String healthCheckKey = "healthCheckConfig";
      String serviceNameKey = "serviceName";
      if (serviceConfig == null || !serviceConfig.containsKey(healthCheckKey)) {
        return null;
      }
  
      /* schema as follows
      {
        "healthCheckConfig": {
          // Service name to use in the health-checking request.
          "serviceName": string
        }
      }
      */
      Map<String, ?> healthCheck = getObject(serviceConfig, healthCheckKey);
      if (!healthCheck.containsKey(serviceNameKey)) {
        return null;
      }
      return getString(healthCheck, "serviceName");
    }