Likely works similar to Octoprint in that the print is sent from the device to the printer. If you print from SD, some printers can resume directly from their control menu (if enabled in firmware). I have had to resume a print once from Octoprint, and I was able to do so by editing the gcode file, deleting the printing code from start to the last layer. Where it resumed, there was a slight shift on one axis (I think I ended up off by 1 layer), but for the most part it turned out ok.