You can do this by overriding CreateUniqueUserName in default ExternalUserBuilder and also implementing your own ApplicationUserResolver.
https://www.linkedin.com/pulse/resolve-your-owin-external-user-own-way-arvind-gehlot
You can do this by overriding CreateUniqueUserName in default ExternalUserBuilder and also implementing your own ApplicationUserResolver.
https://www.linkedin.com/pulse/resolve-your-owin-external-user-own-way-arvind-gehlot