manufacturerData property
This map shows the manufacturer data of the device.
The key is a 16 bit unsigned short but dart2js doesn't have that data
type so an int is used instead.
The key is the company identifier code which can be found on the
Bluetooth standards website:
https://www.bluetooth.com/specifications/assigned-numbers/company-identifiers/.
The value is a ByteData that contains the device's name.
Implementation
@override
final UnmodifiableMapView<int, ByteData> manufacturerData;