in app/Data/AppUserStore.cs [37:49]
public async Task<IdentityResult> DeleteAsync(AppUser user, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
if (user == null) throw new ArgumentNullException(nameof(user));
var appUser = await _context.Users.FirstOrDefaultAsync(m => m.Id == user.Id);
if (appUser == null) throw new ArgumentException("User Not Found");
_context.Users.Remove(appUser);
await _context.SaveChangesAsync();
return IdentityResult.Success;
}