Generates an response containing the auth uri for user to sign in.
When the credential requests PKCE, the URI also carries the S256 code challenge derived from the credential's code verifier, and the returned credential carries the verifier the later token exchange must send.
An AuthCredential object containing the auth URI and state.
Stores the exchanged credential in the session state.
The session state to store the credential in.
A handler that handles the auth flow in Agent Development Kit to help orchestrates the credential request and response flow (e.g. OAuth flow) This class should only be used by Agent Development Kit.