code: function drainStdoutAndExit(code) {
      if (_DEBUG) warn('(drainStdoutAndExit(%d))', code);
      stdout.on('drain', function () {
          cleanupAndExit(code);
      });
      if (stdoutFlushed) {
          cleanupAndExit(code);
      }
  }
docs: A hacked up version of 'process.exit' that will first drain stdout
  before exiting. *WARNING: This doesn't stop event processing.* IOW,
  callers have to be careful that code following this call isn't
  accidentally executed.
  
  In node v0.6 "process.stdout and process.stderr are blocking when they
  refer to regular files or TTY file descriptors." However, this hack might
  still be necessary in a shell pipeline.