Debug log is painfully slow

[Misiur]

My startup time went up to hours due to log being written slowly

[erfanasbari]

I Think It's because the logging steps are these:

1. open file
2. add log line
3. save file
4. close file

and that will cause slow logging.

if you open server_log.txt and change something and save it while the server is running you will get the error: the file is open in another program and that's why server log doesn't take much time but this plugin logging does !

[maddinat0r]

Writing to log files happens in another thread, so that maybe hints at a slow machine (slow disk I/O, slow CPU) being the real bottleneck here. The log file being opened and closed doesn't have a huge performance overhead, so that's an unlikely cause here.