Applied to the API.
We apply a "Rate Limit" policy in order to stop sending too many messages to Push Notification services. We have only one rule: a "payload/message/data" once sent to a "channel" cannot be re-sent within the next 30 seconds to the same "channel".
If the same "payload/message/data" is sent within 30 seconds a "400" status code will be returned by the API and a
error info about this.