Unity3D: rapidly swap old Input system for New Input System

Old2New.cs

//
// @kurtdekker
//
// How to start using the new input system in place of the old one.
//
// If you've been using Input.* for everything, here is how to start
// using the new input system without a lot of extra fussing around.
//
using UnityEngine;

// you'll need this:
using UnityEngine.InputSystem;

// you'll need something like this in your Packages/manifest.json:
//
//		"com.unity.inputsystem": "1.11.2",
//

public class Old2New : MonoBehaviour
{
	void Update()
	{
		// holding a key down:
		// Input.GetKey(KeyCode.LeftArrow);
		if (Keyboard.current.leftArrowKey.IsPressed())
		{
			Debug.Log("Moving Left!  " + Time.time);
		}

		// down / trigger / edge:
		// Input.GetKeyDown(KeyCode.Space);
		if (Keyboard.current.spaceKey.wasPressedThisFrame)
		{
			Debug.Log("Fire!  " + Time.time);
		}

		// click mouse button
		// Input.GetMouseButtonDown(0)
		if (Mouse.current.leftButton.wasPressedThisFrame)
		{
			// mouse position
			Vector2 position = Mouse.current.position.value;

			Debug.Log("Click mouse Button 0: " + Time.time + " at " + position);
		}

		// hold mouse button
		// Input.GetMouseButton(0)
		if (Mouse.current.leftButton.IsPressed())
		{
			Debug.Log("Hold mouse Button 0: " + Time.time);
		}

		// This portion not yet tested: give it a whirl!
		
		// multi-touch touchscreens
		// Input.touches:
		if (Touchscreen.current != null)
		{
			var toucheControls = Touchscreen.current.touches;

			string touchResult = "";

			foreach( var touchControl in toucheControls)
			{
				var phase = touchControl.phase;
				var value = touchControl.value;

				touchResult += $"{phase} -> {value}, ";
			}

			if (touchResult.Length > 0)
			{
				Debug.Log(touchResult);
			}
		}
	}
}