Any way to detect that a touch is required?

[dhess]

Related to #150, I'd like to build a macOS app that notifies the user when their YubiKey is waiting for a touch. This would be handy when using a YubiKey that doesn't have a blinking LED, or with an iMac (all of the USB ports are on the back of the display).

Is there a way to detect this situation from a standalone application, i.e., from a different application than the one that makes the authentication request? I'm imagining something like polling the current device status, either through this library or libusb.

[semente]

@dhess I found that the command ykinfo -s return the error message "Yubikey core error: timeout" when waiting for a touch.