I wanted to make sure my syslog-ng was doing async logging.

Reading through the documentation I see the flush_lines() option for file() destinations, if unspecified, will use the global default. Then I see that the global setting defaults to 0 but it doesn't explain what that means.

Is it going to do synchronous logging when set to 0? is it going to buffer an unlimited number of lines (flushing just every flush_timeout() number of seconds)? is it going to bite me?