Access wildcarded multiple touches

If I set the binding path to <Touchscreen>/touch*/press like the docs say, how do I access the touches array in code?

For context, I've generated the class for the input asset (ARInputActions). In the Action Editor I have (to simplify) 1 action called ScreenTouches which is set to Action Type = Pass Through and Control Type = Any.

Here's the skimmed class that should access touches via Input Actions. See the Debug.Log that reads with an Hamletic tone and translates to: how do I extract all touches from the context?

But I guess the question could be generalized to how do I access wildcarded Actions?

Code (CSharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using UnityEngine.Assertions;
6. using UnityEngine.XR.ARFoundation;
7. using UnityEngine.InputSystem;
8. using UnityEngine.InputSystem.Controls;
9.  
10. public class ARInteractor : MonoBehaviour
11. {
12.     ARInputActions arInputActions;
13.  
14.    void OnEnable() {
15.         arInputActions.Enable();
16.     }
17.  
18.     void OnDisable() {
19.         arInputActions.Disable();
20.     }
21.  
22.     void Awake()
23.     {
24.         arInputActions = new ARInputActions();
25.     }
26.  
27.      void Start() {
28.      
29.         arInputActions.TouchActions.TouchPress.performed += context => { Debug.Log("WHAT TO DO? WHAT TO DOOOO?"); };
30.  
31.     }
32.  
33. }
34.  

 

To add to that, I half-blindly tried the following hoping it would give some results but I get exceptions due to wrong type being given:

Code (CSharp):

1.  
2. // does it send one TouchControl value? (Error: TValue must be non-nullable)
3. arInputActions.TouchActions.TouchPress.performed += _ => { Debug.Log(_.ReadValue<TouchControl>().touchId); }
4. // does it send one touch at a time? (Runtime errors)
5. arInputActions.TouchActions.TouchPress.performed += _ => { Debug.Log("Touch #: " + ((TouchControl)_.ReadValueAsObject()).touchId); };
6. // does it send all touches at once? (Runtime errors)
7. arInputActions.TouchActions.TouchPress.performed += _ => { Debug.Log("N Touches: " + _.ReadValue<ReadOnlyArray<TouchControl>>().Count); };
8.  

(Read the "_" as context)

In particular, I expected ReadValue<TouchControl> to work but the method wants a non-nullable type so TouchControl isn't accepted.