Unity FPS counter for UI text component with minimal memory allocation

FPSCounter.cs

using System.Text;
using UnityEngine;
using UnityEngine.UI;

public class FPSCounter : MonoBehaviour {

    private static readonly string FPS = " FPS ";
    private static readonly int STRING_SIZE = FPS.Length + 2;

    private Text textField;

    public float updateInterval = 0.5F;

    private float accum = 0;
    private int frames = 0;
    private float timeleft;

    private StringBuilder stringBuilder = new StringBuilder(STRING_SIZE);


    void Awake() {
        textField = GetComponent<Text>();
        timeleft = updateInterval;
    }

    void Update() {
        timeleft -= Time.deltaTime;
        accum += Time.timeScale / Time.deltaTime;
        ++frames;

        if ( timeleft <= 0.0 )
        {
            stringBuilder.Remove(0, stringBuilder.Length);

            int fps = (int)accum / frames;

            stringBuilder.Append(fps);
            stringBuilder.Append(FPS);
            textField.text = stringBuilder.ToString();

            timeleft = updateInterval;
            accum = 0.0F;
            frames = 0;
        }
    }


}