AsyncAwaitUnity.cs

using System;
using System.Threading;
using System.Threading.Tasks;
using UnityEngine;

public class NewBehaviourScript : MonoBehaviour
{
    async void Start() {
        Debug.Log($"Hi 1 From MainThread {Thread.CurrentThread.ManagedThreadId}");
        await Task.Run(async () => {
            Debug.Log($"Hi 1 From ThreadPool {Thread.CurrentThread.ManagedThreadId}");
            await Task.Delay(TimeSpan.FromMilliseconds(500));
            Debug.Log($"Hi 2 From ThreadPool {Thread.CurrentThread.ManagedThreadId}");
        }).ContinueWith(_ => Debug.Log($"Hi 2 From MainThread {Thread.CurrentThread.ManagedThreadId}"), TaskScheduler.FromCurrentSynchronizationContext());
        Debug.Log($"Hi 3 From MainThread {Thread.CurrentThread.ManagedThreadId}");
    }
}