Currently, we have a QLowEnergyAdvertisingData class that allows to set raw data for advertising using setRawData() method.

However, the only backend that seems to support this feature is the outdated Linux Kernel API backend.

It looks like most of the modern backends only allow to set UUID-specific raw data. In other words, the user needs to specify the advertised services, and then for each service some raw data can be added.

Some API examples:

• Apple: CBAdvertisementDataServiceDataKey
• Android: AdvertiseData.Builder.addServiceData()
• Linux D-Bus backend: org.bluez.LEAdvertisement1.ServiceData
• Windows: to be discovered, currently advertising is not implemented

The scope of this task is to design a new API that would allow us to provide service-specific advertising data and to provide the implementation for all supported platforms.

Most probably, the existing setRawData() API should be deprecated and scheduled for removal in the next major release.