Note that the endpoint for this API call is on Cloudbeds!
Use this callback to check if a room (rateplan) is available for booking.
Although information about specific room (rateplan) availability is supposed to be present locally on a channel side, we would like to provide an opportunity to double check if a room (rateplan) is available prior to creating a reservation. Using this callback ensures that due to a possible technical issue leading to a room (rateplan) availability numbers not having been (or having been incorrectly / not in time) delivered to a channel, the room is not overbooked and therefore helps avoid both host and guest frustration when such an over-booking has to be canceled by a host due to physical inability to accomodate.