WIP: feat(gui): Support for verifying written data

[ids1024]

Using feature that was already available in the CLI.

This works, but I'm not quite sure how to fit it in the UI. I don't think it looks quite right here:

[maria-komarova]

@ids1024 @mmstick would someone be able to make screenshots of what happens after someone clicks Next?
If I understand correct, the Check button is to verify the downloaded iso and the verification of what is being flashed happens right now after someone clicks Next?

[mmstick]

There's a GUI Design page in the Wiki https://github.com/pop-os/popsicle/wiki/GUI-Design

[ids1024]

As for the UI for the verification stage, this occurs after flashing. Popsicle reads back the data written to the USB drive to make sure it matches what was in the image.

Since reading is faster than writing, depending on image size and drive speed this seems to happen fast enough that it's easy to miss the verification stage if one isn't very carefully watching the program while it flashes.

[cassidyjames]

Does the verifying happen drive-by-drive once each drive is done flashing, or all at once after all are done flashing?

If the former, I think what you have makes sense, though maybe the title could change to "Flashing & Verifying…" to be more clear the option is enabled, then on the complete page you could add a note about the fact that they were verified as well. e.g.:

______________________________________________________________
|                                                            |
|                          Popsicle               [ Close ]  |
|____________________________________________________________|
|                                                            |
|  ICON  Flashed & Verified!                                 |
|  ICON                                                      |
|        3 drives successfully flashed, verified, and        |
|        ejected. You can unplug and use them now.           |
|                                                            |
|                                                            |
|____________________________________________________________|

If the drives are all verified after they've all been flashed, then it would make sense for this to occur on a new step with its own title. e.g.:

______________________________________________________________
|                                                            |
|                          Popsicle                          |
|____________________________________________________________|
|                                                            |
|  ICON  Verifying…                                          |
|  ICON                                                      |
|        Device 01 [=======================----------------] |
|        Device 02 [=====================------------------] |
|        Device 03 [===------------------------------------] |
|                                                            |
|____________________________________________________________|

[ids1024]

It verifies drive-by-drive when they are done flashing. Good idea about making the button say "Flash & Verify".