Spicy Pixel のConcurrency Kitを使ったサンプルコード。

SpicyTest.cs

using UnityEngine;
using System.Collections;
using System.Threading;
using System.Threading.Tasks;
using SpicyPixel.Threading;
using SpicyPixel.Threading.Tasks;

public class SpicyTest : ConcurrentBehaviour
{
    // Awake
    public virtual void Awake()
    {
        base.Awake();

        m_Thread = new Thread( procOnThread );
        m_Thread.Start();
    }
    // OnApplicationQuit
    void OnApplicationQuit()
    {
        m_Thread.Abort();
    }
    // Update
    void Update()
    {
        if( m_IsActive ){
            m_CountByMainThread ++ ;
        }
        if( Input.GetKeyDown(KeyCode.A) ){
            m_IsActive = true;
        }
    }

    // work on thread
    private void    procOnThread()
    {
        while( true )
        {
            Thread.Sleep(0);

            if( m_IsActive )
            {
                Task.WaitAll(
                    taskFactory.StartNew( callUnityAPI )
                );

                m_CountByOtherThread ++ ;
            }
        }
    }

    // call Unity API
    private void    callUnityAPI()
    {
        m_RealTime = Time.realtimeSinceStartup;
    }

    // member
    private Thread      m_Thread;
    private bool        m_IsActive;
    public int          m_CountByMainThread;
    public int          m_CountByOtherThread;
    public float        m_RealTime;
}