Fast Pair supports an RFCOMM channel for Providers that wish to maintain a persistent connection to a device during operation. When the Provider connects to a supported Seeker, the Seeker will attempt to connect RFCOMM on the following channel:
Once connected, messages can be exchanged in the following format:
|2 - 3||uint16||Additional data length||Mandatory|
|4 - n||Additional data||Optional|
The additional data length and additional data fields should be big endian.