# File lib_core/rucy/server.rb, line 106
    def logging_access(fmt=AccessLog::COMMON_LOG_FORMAT)
      # lock order:
      # (1) Rucy::SyncLogger
      # (2) Rucy::SyncAccessLog
      sync_access_log = @access_log
      @access_log = MultiAccessLog.new
      @access_log.add(AccessLogAdapter.new(@logger, fmt))
      @access_log.add(sync_access_log)
      nil
    end