Abusing yield to expose internal state machine

Program.cs

Console.WriteLine();

var statemachine = new StateMachineInstance();
statemachine.State2();
statemachine.State3();
statemachine.State4();

Console.ReadLine();

StateMachine.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;
using System.Reflection;

public abstract class StateMachine {
    protected Action Action;
    protected IEnumerator CurrentState;

    protected void Init() {
        var type = GetType();
        foreach (var field in type.GetFields(
            BindingFlags.Public |
            BindingFlags.Instance).
            Where(f => f.FieldType == typeof(Action))) {
                field.SetValue(this, BuildAction());
            }
    }

    public StateMachine()
    {
        Init();
        CurrentState = MoveState().GetEnumerator();
        CurrentState.MoveNext();
    }

    protected Action BuildAction() {
        Action x = null;
        x = () => {
            Action = x;
            CurrentState.MoveNext();
        };
        return x;
    }

    protected static void Inaction(string excuse) {
        throw new InvalidOperationException(string.Format($"Error with {excuse}"));
    }

    public abstract IEnumerable MoveState();
}

StateMachineInstance.cs

using System;
using System.Linq;
using System.Collections.Generic;
using System.Collections;
using System.Reflection;

public class StateMachineInstance : StateMachine {
    public readonly Action State1;
    public readonly Action State2;
    public readonly Action State3;
    public readonly Action State4;

    public override IEnumerable MoveState() {
        state1:
            Console.WriteLine("state1");
            yield return null;
            if (Action == State2) { goto state2; }

            Inaction("state1");
        state2:
            Console.WriteLine("state2");
            yield return null;
            if (Action == State1) { goto state1; }
            if (Action == State3) { goto state3; }

            Inaction("state2");
        state3:
            Console.WriteLine("state3");
            yield return null;
            if (Action == State3) { goto state3; }
            if (Action == State4) { goto state4; }

            Inaction("state3");
        state4:
            Console.WriteLine("state4");
            yield return null;
            if (Action == State1) { goto state1; }

            Inaction("state4");
    }
}