GoFrom.cs

using System;
using System.Collections;
using UnityEngine;

public class GoFrom : MonoBehaviour
{
	static GoFrom _instance;
	static GoFrom instance
	{
		get
		{
			if ( _instance == null )
			{
				_instance = new GameObject("ZeroToOne").AddComponent<GoFrom>();
			}
			return _instance;
		}
	}

	public static Coroutine ZeroToOne( float time, Action<float> tick, float delay = 0, Action finished = null )
	{
		return instance.StartCoroutine(instance.ZeroToOneRoutine(time, tick, delay, finished));
	}

	IEnumerator ZeroToOneRoutine( float time, Action<float> tick, float delay, Action finished )
	{
		var timer = 0f;
		while ( timer < time )
		{
			yield return null;
			timer += Time.deltaTime;
			tick.Invoke(Mathf.Clamp01(timer / time));
		}

		if ( finished != null )
		{
			finished.Invoke();
		}
	}
}