Q: GoogleJsonWebSignature.Payload JsonWebToken Contents I'm working on an application that requires google sign in for its user data.
I'm getting my JWT payload like the following
payload = await GoogleJsonWebSignature.ValidateAsync(userToken);

I'd like to get some kind of identifier for sql lookup. It's noted by the documentation that email is not suitable for primary key(which I am not doing). 
Does that mean it is not acceptable to lookup an entry using the email as well, and then use the PK after the initial lookup?
If this is not an acceptable solution, how might I go about looking up my users with authenticated information provided by google?

A: You can use the subject field of the payload.

private java.lang.String subject
Subject claim identifying the principal that is the subject of the JWT or null for none.

From google:

Note: A Google account's email address can change, so don't use it to
identify a user. Instead, use the account's ID, which you can get on
the client with GoogleSignInAccount.getId, and on the backend from the
sub claim of the ID token.

