I am using IdentityServer4. I have configured Google authentication middleware as seen here. However, the redirect uri registered with Google is <domain>/signin-google. Additionally, I know that the ExternalLoginCallback endpoint gets called after I have authenticated with Google and after the redirect uri that is registered with Google has been called (/signin-google).
My question is what happens between /signin-google and the call to /ExternalLoginCallback? What method(s) in the Google middleware are triggered once the browser is redirected to /signin-google but before the application/middleware eventually makes it to /ExternalLoginCallback?