apollo-client/src/main/java/com/ctrip/framework/apollo/internals/YamlConfigFile.java/YamlConfigFile/toProperties
class YamlConfigFile:  private Properties toProperties() {
    if (!this.hasContent()) {
      return propertiesFactory.getPropertiesInstance();
    }

    try {
      return ApolloInjector.getInstance(YamlParser.class).yamlToProperties(getContent());
    } catch (Throwable ex) {
      ApolloConfigException exception = new ApolloConfigException(
          "Parse yaml file content failed for namespace: " + m_namespace, ex);
      Tracer.logError(exception);
      throw exception;
    }
  }