apollo-client/src/main/java/com/ctrip/framework/apollo/ConfigService.java/ConfigService/getRegistry
class ConfigService:  private ConfigRegistry getRegistry() {
    if (m_configRegistry == null) {
      synchronized (this) {
        if (m_configRegistry == null) {
          m_configRegistry = ApolloInjector.getInstance(ConfigRegistry.class);
        }
      }
    }

    return m_configRegistry;
  }