Stupid question, but what is the recommended way to return a value from a method?

[MeltdownInteractive]

All the code examples have void as the return type.

But I would like to create some of my methods that make a REST API call return a value. What is the recommended method to do this with this Promise based library considering it doesn't support async/await?

I'm thinking of just having one of my method params being an Action

i.e

public void Post(string param1, Action<bool, string> callback)
        {

            RestClient.Post<Post>(currentRequest)

                .Then(result =>

                {

                    callback(true, JsonUtility.ToJson(result, true));

                })

                .Catch(err => callback(false, err.Message));
        }