How to use RenewTokens?

[suntong]

RenewTokens method is "for renew access and refresh tokens", and it accepts a string which will satisfy:

return strconv.ParseInt(strings.Split(refreshToken, ".")[1], 0, 64)

That's all I can dig out so far and I'm still not sure what kind of string should be passed to it and the meaning of them.

An example please. thx.