writing log file stopps after short time during active process

[ChMG]

Describe the bug

With the command line argument -L you can enable writing a log file.
At my tests I see the log output stopps after some time during the active bngblaster test.

As soon as you stopps the bngblaster the rest of the log will be written.
So in the end you have an compleate log, but during the test you cannot see all log entries.

This is especially annoying when using the bngblaster-controller, where you don´t have an console output.

With the bngblaster-controller I see the same problem with the run.stdout file.

The changes from #378 don´t fixes the problem for me.

To Reproduce

• start bngblaster
  sudo bngblaster -C config.json -L test.log -l error -l loss -l dhcp -l pppoe -l debug
• at an second console tail -f test.log
  --> log is incompleate
• stop bngblaster
  --> log is compleate

with bngblaster controller:

• start test
• at an console tail -f run.log or tail -f run.stdout
  --> log is incompleate
• stop test
  --> log is compleate

Version (bngblaster -v): 0.9.34

Additional context

I have test some code changes at the bngblaster and I can fix the problem by set the file stream buffers to 0.
This means that every line has to be written immediately.

I also create a pull request with my changes.

[ChMG]

Okay, another finding.

On my production system, which has significantly more resources, writing to and retrieving run.log works with the bngblaster-controller after fix #378.

However, writing to ron.stdout still doesn't work reliably.