Delete O365 group with associated site collection via Graph SDK

In order to delete O365 group (Azure AD group + Sharepoint Online site collection) via .Net Graph SDK the following code may be used:

public static bool DeleteGroup(string groupId)
{
    try
    {
        if (string.IsNullOrEmpty(groupId))
        {
            return false;
        }

        var graphClientApp = new GraphServiceClient(new AzureAuthenticationProviderAppPermissions());
        if (graphClientApp == null)
        {
            return false;
        }

        graphClientApp.Groups[groupId].Request().DeleteAsync().GetAwaiter().GetResult();

        return true;
    }
    catch (Exception x)
    {
        return false;
    }
}

public class AzureAuthenticationProviderAppPermissions : IAuthenticationProvider
{
    // implement own authentication logic for app permissions
}

Azure AD group will be deleted immediately while associated site collection will be deleted with some delay (usually few minutes).