Github: https://github.com/Unity-Technologies/InputSystem/issues/469
Forum: https://forum.unity.com/threads/how-to-update-input-system-manually.640105/

In Project Setting for Input (NEW), if Update Mode is set to "Process Events Manually", the ISX doesn't work anymore.

Repro:
1. Download attached project: ManualUpdate
2. Download ISX package if needed: https://github.com/Unity-Technologies/InputSystem
3. Open SimpleDemo scene
4. Enter Playmode and try to move around with WASD
(Optinal)
5. Go to ProjectSettings -> Input(NEW) -> Update Mode and change it to other options
6. Enter Playmode again and try move around.

Actual: When using Manual update, calling "UnityEngine.Experimental.Input.InputSystem.Update(InputUpdateType.Manual)" does not update the queued input events.

Explanation about project:
The project calls manual update and a debug message saying "ManualUpdate Coroutine" every 3 seconds.
If the message appears in the Console with no input executed, it means the manual update does not process any input events queued between updates.