This callback listener is fired when the IFTTTMakerChannelTrigger
receives a GPIO pin change that invokes the trigger. This listener
provides the consumer an opportunity to be notified of the trigger event,
to optionally abort the triggered event before sending data to the IFTTT
Maker Channel API, or an opportunity to override any data payload values
before transmitting to the IFTTT Maker Channel API.
event - the IFTTTMakerChannelTriggerEvent event object that
contains details about the GPIO pin, pin state, and
IFTTT Maker Channel event name and data payload.
Return a 'true' value to continue trasmitting the trigger data to
the IFTTT Maker Channel API. Return a 'false' value to abort
bypass sending the triggered event to IFTTT.