Throttling messages throw error

[paulmand3l]

Receiving a throttling message on the username/throttle topic throws an error:

Traceback (most recent call last):
  File "code.py", line 85, in <module>
  File "adafruit_io/adafruit_io.py", line 244, in loop
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 706, in loop
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 733, in _wait_for_msg
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 273, in _handle_on_message
  File "adafruit_io/adafruit_io.py", line 183, in _on_message_mqtt
IndexError: list index out of range

[brentru]

I'll look at this and PR, it should raise a AdafruitIO_ThrottleError.

https://github.com/adafruit/Adafruit_CircuitPython_AdafruitIO/blob/master/adafruit_io/adafruit_io_errors.py#L30

[brentru]

Ok, I was able to replicate this

Publishing 20 to DemoFeed.
Traceback (most recent call last):
  File "code.py", line 128, in <module>
  File "/lib/adafruit_io/adafruit_io.py", line 244, in loop
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 706, in loop
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 733, in _wait_for_msg
  File "adafruit_minimqtt/adafruit_minimqtt.py", line 273, in _handle_on_message
  File "/lib/adafruit_io/adafruit_io.py", line 183, in _on_message_mqtt
IndexError: list index out of range```