A real framerate counter for Unity

RealFramerate.cs

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

[ExecuteInEditMode]
[RequireComponent(typeof(Camera))]
public class RealFramerate : MonoBehaviour {

    public int framerate { get { return _framerate; } }
    private int _framerate;

    public bool maxPower = true;
    private bool _maxPower = true;

    private Queue<float> _deltas = new Queue<float>();

    private void Awake() {
        Application.targetFrameRate = -1;
        QualitySettings.vSyncCount = 0;
    }

    // Update is called once per frame
    void Update () {
        if (_maxPower != maxPower) {
            _maxPower = maxPower;
            Application.targetFrameRate = _maxPower? -1 : 60;
            QualitySettings.vSyncCount = _maxPower? 0 : 1;
        }
        _deltas.Enqueue(Time.deltaTime);
        _framerate = (int)Mathf.Round(1f / _deltas.Sum(o => o) * _deltas.Count);
        int dampFrames = Mathf.Clamp(_framerate, 1, 250);

        while (_deltas.Count > dampFrames)
            _deltas.Dequeue();
    }

    private void OnGUI() {
        GUI.Label(new Rect(0, 0, Screen.width, Screen.height), _framerate + " FPS");
    }
}