errors.go
func GetContextError(err error) error {
	if err == context.DeadlineExceeded {
		return ErrTimeout
	}
	if err == context.Canceled {
		return ErrRequestCancelled
	}
	return err
}
func GetContextError(err error) error {
	if err == context.DeadlineExceeded {
		return ErrTimeout
	}
	if err == context.Canceled {
		return ErrRequestCancelled
	}
	return err
}
// GetContextError converts the context error to a tchannel error.