code: func ReadFile(hfs http.FileSystem, name string) ([]byte, error) {
  	fh, err := hfs.Open(name)
  	if err != nil {
  		return nil, err
  	}
  	var buf bytes.Buffer
  	_, err = io.Copy(&buf, fh)
  	fh.Close()
  	return buf.Bytes(), err
  }
docs: // ReadFile reads the contents of the file of hfs specified by name.
  // Just as ioutil.ReadFile does.