OptionalidentityIdentity provider name sent as identity_provider with the token request,
telling the token endpoint which IdP issued the code. Defaults to
ESPIdProvider.WECHAT when wechatTokenOnly is true; otherwise omitted
unless provided.
OptionalwechatWhen true, adds the wechat_token_only=true flag to the token request.
Required by the WeChat (CN region) token-only exchange.
Options for exchanging an OAuth authorization code for tokens via
ESPRMAuth.loginWithOauthCode.