apollo-client/src/main/java/com/ctrip/framework/apollo/internals/LocalFileConfigRepository.java/LocalFileConfigRepository/updateFileProperties
class LocalFileConfigRepository:  private synchronized void updateFileProperties(Properties newProperties, ConfigSourceType sourceType) {
    this.m_sourceType = sourceType;
    if (newProperties.equals(m_fileProperties)) {
      return;
    }
    this.m_fileProperties = newProperties;
    persistLocalCacheFile(m_baseDir, m_namespace);
  }