Unity でヒープにごみを出さない WaitForSeconds

VariableWaitForSeconds.cs

// BEGIN MIT LICENSE BLOCK //
//
// Copyright (c) 2016 dskjal
// This software is released under the MIT License.
// http://opensource.org/licenses/mit-license.php
//
// END MIT LICENSE BLOCK   //
/* 使い方
[SerializeField]
float interval = 1;

void Start() {
    StartCoroutine(coroutine());
}

IEnumerator coroutine() {
    var wfs = new VariableWaitForSeconds(interval);
    while (true) {
        // 実行するコード

        yield return wfs.ChangeInterval(interval);
    }
}
*/
using UnityEngine;
using System.Collections;

public class VariableWaitForSeconds : CustomYieldInstruction {

    private float elapsed;
    public float Interval { get; set; }
    public override bool keepWaiting
    {
        get
        {
            elapsed += Time.deltaTime;
            var isKeepWaiting = Interval >= elapsed;
            if (!isKeepWaiting) {
                // elapsed -= Interval だと 10 秒間隔のあとに 1 秒間隔に変更されたときに対応できない
                elapsed = 0;
            }
            return isKeepWaiting;
        }
    }

    public VariableWaitForSeconds(float interval) {
        elapsed = 0;
        Interval = interval;
    }

    public IEnumerator ChangeInterval(float interval) {
        Interval = interval;
        return this;
    }
}