When you Checkpoint a VM, at what point is the state saved?

Question

In Hyper-V, if you create a Standard Checkpoint on a VM, is the disk and memory state frozen when you start creating the checkpoint, or when the checkpoint has finished saving, or at some other point in between the two?

Answer 1

I did some informal testing in Hyper-V in Windows 11 with an 8GB VM.

My findings are that roughly a second after clicking Checkpoint, the VM freezes for a little less than a second, and that's the point where the state is saved. (The checkpoint continues to save in the background after this.)

Reverting takes me back to the point where the VM froze.