init()

The init function will enumerate all USB devices and find the first streamdeck device.

It will not be opened at this time, but the module variables below will be set to the found device

serial - will be set to the serial number of the device

firmware - will be set to the reported firmware version of the device

type - will be set to a string describing the device

buttons - will be set to the number of buttons the device supports

pid - will be set to the found pid (product ID) of the device

vid - is set to 0x0fD9, the vendor ID of Elgato

callback holds the address of the callback function which is called when there is a button press or release event. That function shuold be set with the open function and not manipulated directly