status: request status (1 = success)
acknowledged: number indicating whether (1) or not (0)
notification has been acknowledged
acknowledged_at: Unix timestamp indicating when notification was
acknowledged, or 0
acknowledged_by: key of the user who first acknowledged the
notification, or ""
acknowledged_by_device: name of the device on which the first
user acknowledged the notification
last_delivered_at: Unix timestamp of when the notification was
last acknowledged, or 0
expired: whether (1) or not (0) the notification has expired
expires_at: Unix timestamp indicating when the notification will
no longer be retried
called_back: whether (1) or not (0) the callback URL has been
visited
called_back_at: Unix timestamp indicating when the callback URL
was visited
request: unique request ID
errors: a list of error messages (only for unsuccessful requests)
raw: the raw httr::response object