public Task <TUser> FindByNameAsync(string userName)
{
if (string.IsNullOrEmpty(userName))
{
throw new ArgumentException("Null or empty argument: userName");
}
TUser result = IdentityUserRepository.GetByUserName(userName) as TUser;
// Should I throw if > 1 user?
if (result != null)
{
return(Task.FromResult <TUser>(result));
}
return(Task.FromResult <TUser>(null));
}