I discovered that I couldn't use this library for the Adafruit Feather M0 which is a SAMD21 board. The reason was that the USB connection is named Serial1 and not SerialUSB as for the Arduino Zero. I figured it would be best to use the SERIAL_PORT_USBVIRTUAL define that is set in the board files. This way the library automatically uses the correct port.
I discovered that I couldn't use this library for the Adafruit Feather M0 which is a SAMD21 board. The reason was that the USB connection is named Serial1 and not SerialUSB as for the Arduino Zero. I figured it would be best to use the SERIAL_PORT_USBVIRTUAL define that is set in the board files. This way the library automatically uses the correct port.