Unity3D iOS post build process to replace app delegate source

ReplaceDelegatePostProcess.cs

using UnityEditor;
using UnityEditor.Callbacks;
using UnityEditor.iOS.Xcode;
using UnityEngine;

namespace QuickActionsiOS
{
	public class ReplaceDelegatePostProcess : ScriptableObject
	{
		/// <summary>
		/// Put your custom delegate file here via inspector
		/// </summary>
		public DefaultAsset NewDelegateFile;

		private const string DefaultDelegateName = "UnityAppController.mm";

		[PostProcessBuild(999)]
		public static void OnPostProcess(BuildTarget buildTarget, string buildPath)
		{
			if(buildTarget != BuildTarget.iOS) return;

			//creating instance of scriptable object to get file path
			var instance = ScriptableObject.CreateInstance<ReplaceDelegatePostProcess>();
			var delegateFile = instance.NewDelegateFile;
			DestroyImmediate(instance);
			if(delegateFile == null) return;

			//get path to xCode project and project itself
			var projectPath = PBXProject.GetPBXProjectPath(buildPath);
			var xCodeProject = new PBXProject();
			xCodeProject.ReadFromFile(projectPath);
			
			//get paths to new and old delegate
			var newDelegatePath = AssetDatabase.GetAssetPath(delegateFile);
			var delegatePath = buildPath + "/Classes/";
			var oldDelegatePath = delegatePath + DefaultDelegateName;
			
			//remove old delegate, add new one with default unity name
			FileUtil.DeleteFileOrDirectory(oldDelegatePath);
			FileUtil.CopyFileOrDirectory(newDelegatePath, delegatePath + DefaultDelegateName);

			//save changes to xCode project
			xCodeProject.WriteToFile(projectPath);
		}
	}
}