Unity Deferred

AsyncError.cs

public class AsyncError {

	public string Message { get; private set; }
    
    public AsyncError(string _message) {
        Message = _message;
    }
}

ExempleDeferred.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ExempleDeferred : MonoBehaviour {

    public int Pokemon1 = 1;
    public int Pokemon2 = 2;

    private void OnGUI() {
        if (GUI.Button(new Rect(200,0,200,100),"calc biggest pokemon")) {
            StartCoroutine(GetBiggestPokemon(Pokemon1, Pokemon2));
        }
    }



    IEnumerator GetBiggestPokemon(int id1, int id2) {
        Debug.Log("hello");
        Deferred<PokemonData> firstPokemon = new Deferred<PokemonData>();
        yield return GetPokemon(id1, firstPokemon);
        if (firstPokemon.Error != null) {
            Debug.LogError(firstPokemon.Error.Message);
            yield break;
        }
        Debug.Log("First pokemon is " + firstPokemon.Value.name);

        Deferred<PokemonData> secondPokemon = new Deferred<PokemonData>();
        yield return GetPokemon(id2, secondPokemon);
        if (secondPokemon.Error != null) {
            Debug.LogError(secondPokemon.Error.Message);
            yield break;
        }
        Debug.Log("Second pokemon is " + secondPokemon.Value.name);

        PokemonData biggest = firstPokemon.Value.weight > secondPokemon.Value.weight ? firstPokemon.Value : secondPokemon.Value;
        Debug.Log("Biggest pokemon is " + biggest.name);
    }
    
    // Make a request to the pokemon api, parse it and resolve with a PokemonData
    IEnumerator GetPokemon(int id, Deferred<PokemonData> _pokemonDefered) {
        Deferred<string> apiRequest = new Deferred<string>();
        yield return RequestCoroutine("http://pokeapi.co/api/v2/pokemon/"+id, apiRequest);
        if (apiRequest.Error != null) {
            _pokemonDefered.Catch(apiRequest.Error);
            yield break;
        }
        _pokemonDefered.Resolve(JsonUtility.FromJson<PokemonData>(apiRequest.Value));
    }

    IEnumerator RequestCoroutine(string url, Deferred<string> _deferred) {
        WWW request = new WWW(url);
        yield return request;
        if (request.isDone && request.error == null) {
            _deferred.Resolve(request.text);
        } else {
            _deferred.Catch(request.error);
        }
    }



	class Deferred<T> {
        public T Value { get; private set; }
        public bool IsCompleted { get; private set; }
        public AsyncError Error { get; private set; }

        public void Resolve(T _value) {
            Value = _value;
            IsCompleted = true;
        }
        public void Catch(AsyncError _err) {
            Error = _err;
            IsCompleted = true;
        }
        public void Catch(string _message) {
            Catch(new AsyncError(_message));
        }
    }

    
}

PokemonData.cs

[System.Serializable]
public class PokemonData {

    public string name;
    public int height;
    public float weight;

}