Does anyone know how to use the DJIRTKNetworkServiceProvider correctly?
I tried it several times and i allways have some errors.
Maybe someone has an sample code for it?

I received some guide for the Android, hope this any help.

Here are some steps about how to use the RTK via MSDK.
First, please ensure that which RTK solution you are using:
setReferenceStationSource
The MSDK provides three solutions:
1.BASE_STATION

2.CUSTOM_NETWORK_SERVICE（M210 V2 RTK, M300 RTK, P4M and P4RTK supported). Using the third-party NTRIP RTK sever.
-Set the network setting with method setCustomNetworkSettings (account provided by the third-party).
-To enable network service startNetworkService to transmit the RTK data.

3.NETWORK_RTK(supported by the P4RTK, P4M, M300 RTK )
-This service should be ordered from the DJI first.
-To add the 'com.dji:library-networkrtk-helper:1.0' and set the coordinate system setNetworkServiceCoordinateSystem.
-To ensure that you have activated the network service activateNetworkService, just need active when using it for the first time.(Please igone it, if you have activated the service plan in the DJI pilot software before.)
-To enable network service startNetworkService to transmit the RTK data.
Second, enable the RTK with setRtkEnabled.
Last, to listen to the isRTKBeingUsed which determine that the RTK data was used by the flight controller or not. And to getPositioningSolution status, FIXED_POINT solution positioning (most accurate).

By the way, all the step can be also referred on the DJI pilot application.