Get the response body of the request to FCM. If an error occured this will contain the description. If the send went OK the body will contain a name which is the ID of the sent message. The returned string is valid for the lifetime of the notification object.
NABTO_DEVICE_DECL_PREFIX const char* NABTO_DEVICE_API
- [in] The notification to get response body from
The response body string. NULL if send has not resolved with NABTO_DEVICE_EC_OK