function formatArgs(args) {
		  var name = this.namespace;
		  var useColors = this.useColors;

		  if (useColors) {
		    var c = this.color;
		    var prefix = '  \u001b[3' + c + ';1m' + name + ' ' + '\u001b[0m';

		    args[0] = prefix + args[0].split('\n').join('\n' + prefix);
		    args.push('\u001b[3' + c + 'm+' + exports.humanize(this.diff) + '\u001b[0m');
		  } else {
		    args[0] = new Date().toUTCString()
		      + ' ' + name + ' ' + args[0];
		  }
		}
Set response header fields, most
fields may be pre-defined.

@param {String} path
@param {Object} stat
@api private