FuncDelegateTest.cs

using UnityEngine;
using System.Collections;
using System;

public class FuncDelegateTest : MonoBehaviour
{
  void Start()
  {
    Func<GameObject> callback = delegate() { return null; };
    RunCallback(callback);
  }

  void RunCallback(Func<GameObject> callback)
  {
    Debug.Log(callback());
  }
}