Get a list of groups that Azure AD user belongs to in claims for .Net Core

I am trying to get the list of groups in Azure AD user belongs to in .Net Core with token generated in the "implicit flow". There is no group information.

I am using "implicit flow" as mentioned in the following link: .NET Core and Azure Active Directory integration

The following shows how to do it in the .NET Framework but .NET Core don't have the 'ActiveDirectoryClient' class.

Get a list of groups that Azure AD user belongs to in claims

Any Help is much appreciated!

derek