code: function loadFile(name, dir, options) {
    var pathname = path.normalize(path.join(options.prefix, name));
    var obj = {};
    var filename = (obj.path = path.join(dir, name));
    var stats = fs.statSync(filename);
    var buffer = fs.readFileSync(filename);
  
    obj.cacheControl = options.cacheControl;
    obj.maxAge = obj.maxAge ? obj.maxAge : options.maxAge || 0;
    obj.type = obj.mime = mime.lookup(pathname) || "application/octet-stream";
    obj.mtime = stats.mtime;
    obj.length = stats.size;
    obj.md5 = crypto.createHash("md5").update(buffer).digest("base64");
  
    debug("file: " + JSON.stringify(obj, null, 2));
    if (options.buffer) obj.buffer = buffer;
  
    buffer = null;
    return obj;
  }
docs: load file and add file content to cache
  
  @param {String} name
  @param {String} dir
  @param {Object} options
  @return {Object}
  @api private