How to do 'out' in a Func in c#

Question

I am using a library which measure metrics for running code. The usage of the library is something like this.

_Library.Wrap("AnyStringForMetrics", Func<T>);

So whatever I pass into the Func as a lambda will be measured and result of it will be returned.

At the moment, I have method where I want to measure this line where it tries to create or get a user with that id. (newlyCreated will be true if the user was created)

public User GetOrCreate(long id, out bool newlyCreated) {
    // some random checks
    return UserDatabase.GetOrCreate(id, out newlyCreated);
}

But now, if I try to wrap my code around

public User GetOrCreate(long id, out bool newlyCreated) {
    // some random checks
    return _Library.Wrap(
        "UserGetOrCreate", () => UserDatabase.GetOrCreate(id, out newlyCreated));
}

I will get an exception for using "out" inside lambda expression. How should I resolve this?

If possible please write out a concrete code example... Thanks.

Answer 1

Use a ValueTuple as return type instead and thus avoid using an out parameter.

public (User user, bool newlyCreated) GetOrCreate(long id) {
    var user = ....;
    bool created = ....;
    return (user, created);
}

and map it to Func<(User, bool)>.