code: func newError(message string) *Error {
  	switch {
  	case strings.HasPrefix(message, "rpc: service/method request ill-formed"):
  		return NewError(errMethod.Code, message)
  	case strings.HasPrefix(message, "rpc: can't find service"):
  		return NewError(errMethod.Code, message)
  	case strings.HasPrefix(message, "rpc: can't find method"):
  		return NewError(errMethod.Code, message)
  	default:
  		return NewError(errServer.Code, message)
  	}
  }
docs: // newError returns an Error with auto-detected code for given message.