Syslog messages sometimes not prefixed correctly about stenographer HOT 1 OPEN

These all appear to be coming from stenotype, so my guess is it's because of the fact that we pass a syslog Logger into stenotype as STDOUT/STDERR. In stenographer.go:

logwriter, err := syslog.New(syslog.LOG_USER|syslog.LOG_INFO, "stenographer")
...
stenotypeOutput = logwriter // for stenotype
...
env.StenotypeOutput = stenotypeOutput

In env/env.go:

cmd.Stdout = d.StenotypeOutput
cmd.Stderr = d.StenotypeOutput

We've got C writing to stderr, and (correctly) flusing after each write using flush here in util.h:

~LogLine() {
  ss_ << "\n";
  std::cerr << ss_.str() << std::flush;

But that flushes into STDERR, which Go picks up and tries to pipe into the syslog logwriter. It uses an os.Pipe for this that it created with writerDescriptor. I expect it's this pipe that, in certain circumstances, buffers two lines together into a single Write call to the syslog writer.

from stenographer.