ThreadWorker.cs

// The MIT License
// Copyright (c) Richard Meredith AB
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

//--------------------
// this is source code related to the blog post I wrote on Multithreading back in 2017
// 		https://richardmeredith.net/2017/11/pause-resume-abort-multithreading-unity/
// Moving this code into a Gist for archival purposes

// The blog post was written a long time ago (using Unity 5.5 apparently!) and as such 
// the implementation details are outdated and I'm not familiar enough with Unity these
// days to know what the correct approach would be. I'm pretty sure Unity has similar
//  helper classes built-in now, but the concepts and information here are still useful

using System;
using System.Collections;
using System.Threading;

public class ThreadWorker
{
	private Thread ChildThread = null;
	private EventWaitHandle SuspendHandle = new EventWaitHandle(true, EventResetMode.ManualReset);
	private EventWaitHandle AbortHandle = new EventWaitHandle(false, EventResetMode.ManualReset);
	private bool WantAbort = false;

	public ThreadWorker(IEnumerator threadImplementation) : this()
	{
		Start(threadImplementation);
	}

	public void Start(IEnumerator threadImplementation)
	{
		ChildThread = new Thread(ThreadLoop);
		ChildThread.Start(threadImplementation);
	}

	public void Resume()
	{
		SuspendHandle.Set();
	}

	public void Suspend()
	{
		if(!WantAbort)
			SuspendHandle.Reset();
	}

	public void Abort(bool block=true)
	{
		WantAbort = true;

		Resume();

		if(block)
			AbortHandle.WaitOne();
	}

	private void ThreadLoop(object threadImplementation)
	{
		try
		{
			var impl = threadImplementation as IEnumerator;

			while(!WantAbort && impl.MoveNext())
			{
				if(WantAbort)
					break;

				SuspendHandle.WaitOne();
			}
		}
		catch(Exception e)
		{
			WantAbort = true;
			UnityEngine.Debug.LogException(e);
		}

		AbortHandle.Set();
		ChildThread = null;
	} 

	public bool IsRunning() {return ChildThread != null;}
	public bool IsCompleted() {return ChildThread == null;}


#if UNITY_EDITOR
	public ThreadWorker()
	{
		UnityEditor.EditorApplication.playmodeStateChanged += HandleEditorPlayModeChanged;
	}

	~ThreadWorker()
	{
		UnityEditor.EditorApplication.playmodeStateChanged -= HandleEditorPlayModeChanged;
	}

	void HandleEditorPlayModeChanged()
	{
		if(IsRunning())
		{
			if(UnityEditor.EditorApplication.isPaused)
				Suspend();
			else
				Resume();
		}
	}
#else
	public ThreadWorker() {}
#endif
}