code: function ProblemLogger(options) {
  	options = options || {};
  	ConsoleLogger.call(this);
  	const tmpdir = require('os').tmpdir();
  	this.filename = path.join(tmpdir, 'logger-' + (+new Date()) + '.log');
  	this.name = options.problemLogName || ((options.name || 'problem') + '.log');
  	this.stream = fs.createWriteStream(this.filename);
  	this.write({ level: bunyan.TRACE, msg: util.format('log file opened') });
  	streams.push(this);
  }
docs: Logger stream that will only write out a log file
  if the process exits non-zero in the current directory
  
  @param {Object} options - options
  @constructor