Can I get the Id of a newly created IdentityUser

I have all my membership classes in a class library I am using in an MVC app.  Here is what I am trying:

public DataResult CreateUser(BasicUserVM uservm)
        {
            DataResult dresult = new DataResult();

            ColossalUser user = new ColossalUser { Email = uservm.Email, UserName = uservm.UserName };

            IdentityResult result = _userManger.Create(user, uservm.Password);
           
            ColossalRole role = _rolemanager.FindByName(uservm.Role);

            if(role == null)
            {
                _rolemanager.Create(new ColossalRole(uservm.Role));
                role = _rolemanager.FindByName(uservm.Role);
            }

            var retUser = _userManger.FindByName(user.UserName);

            _userManger.AddToRole(retUser.Id, role.Name);

            if(result.Succeeded)
            {
                dresult.resultType = "success";
                dresult.message = "user created";
            }
            else
            {
                dresult.resultType = "error";
                dresult.message = "user repo error";
                foreach(var s in result.Errors)
                {
                    dresult.exception += s.ToString() + " ";
                }
            }

            return dresult;
            

        }//end of CreateUser()

the retUser is null. How can I create a user and within the same function call get the user Id so I can add them immediately to a role?

Thanks in advance!