https://forum.unity.com/threads/async-await-in-editor-script.481276/

EditorAsyncPump.cs

using System.Reflection;
using System.Threading;
using UnityEditor;
using UnityEngine;

public static class EditorAsyncPump {
    [InitializeOnLoadMethod]
    static void Initialize() {
        Debug.Log("Pump Initialize");
        EditorApplication.update += ExecuteContinuations;
    }
    static void ExecuteContinuations() {
        if (EditorApplication.isPlayingOrWillChangePlaymode) {
            // Not in Edit mode, don't interfere
            return;
        }
        var context = SynchronizationContext.Current;
        if (_execMethod == null) {
            _execMethod = context.GetType().GetMethod("Exec", BindingFlags.NonPublic | BindingFlags.Instance);
        }
        _execMethod.Invoke(context, null);
    }
    static MethodInfo _execMethod;
}

// 來源： https://forum.unity.com/threads/async-await-in-editor-script.481276/