Unable to send data to the main thread. Android, tdlib

Question

I'm trying to write a telegram-based mini-application. Connected tdlib (library for sending requests to telegram servers). All responses from the telegram server are returned to the overridden onResult() method of the class inherited from Client.ResultHandler.

class TelegramResultHandler: Client.ResultHandler {

private val _authState = MutableLiveData<Authentication>()
val authState: LiveData<Authentication> get() = _authState

override fun onResult(data: TdApi.Object) {
    when (data.constructor) {
        TdApi.UpdateAuthorizationState.CONSTRUCTOR -> {
            onAuthorizationStateUpdated((data as TdApi.UpdateAuthorizationState).authorizationState)
        }
        else -> Log.d(TAG, "Unhandled call: $data.")
    }
}


private fun onAuthorizationStateUpdated(authorizationState: TdApi.AuthorizationState) {
    when (authorizationState.constructor) {
        TdApi.AuthorizationStateWaitTdlibParameters.CONSTRUCTOR -> {
            Log.d(TAG, "onResult: AuthorizationStateWaitTdlibParameters")
        }
        TdApi.AuthorizationStateWaitEncryptionKey.CONSTRUCTOR -> {
            Log.d(TAG, "onResult: AuthorizationStateWaitEncryptionKey")
        }
        TdApi.AuthorizationStateWaitPhoneNumber.CONSTRUCTOR -> {
            Log.d(TAG, "onResult: AuthorizationStateWaitPhoneNumber")
        }
        TdApi.AuthorizationStateWaitCode.CONSTRUCTOR -> {
            Log.d(TAG, "onResult: AuthorizationStateWaitCode")
            authState.postValue(Authentication.WAIT_FOR_CODE)
        }
        TdApi.AuthorizationStateWaitPassword.CONSTRUCTOR -> {
            Log.d(TAG, "onResult: AuthorizationStateWaitPassword")
            authState.postValue(Authentication.WAIT_FOR_PASSWORD)
        }
        TdApi.AuthorizationStateReady.CONSTRUCTOR -> {
            Log.d(TAG, "onResult: AuthorizationStateReady")
            authState.postValue(Authentication.AUTHENTICATED)
        }
        TdApi.AuthorizationStateLoggingOut.CONSTRUCTOR -> {
            Log.d(TAG, "onResult: AuthorizationStateLoggingOut")
        }
        TdApi.AuthorizationStateClosing.CONSTRUCTOR -> {
            Log.d(TAG, "onResult: AuthorizationStateClosing")
        }
        TdApi.AuthorizationStateClosed.CONSTRUCTOR -> {
            Log.d(TAG, "onResult: AuthorizationStateClosed")
        }
        else -> Log.d(TAG, "Unhandled authorizationState: $authorizationState.")
    }
}


enum class Authentication {
    UNAUTHENTICATED,
    WAIT_FOR_NUMBER,
    WAIT_FOR_CODE,
    WAIT_FOR_PASSWORD,
    AUTHENTICATED,
    UNKNOWN
}

I am unable to pass this data to the main thread for display. For example, during authorization, after sending the code, the client can log in or request a cloud password, but information about this can only be obtained in onResult(), and it cannot be transmitted from there.

I tried to create a variable of the MutableLiveData type and send data using the postValue() method, but during the debugging process, I notice that the data has changed, but the subscriber does not react in any way. In a Fragment:

private val resultHandler = TelegramResultHandler()

resultHandler.authState.observe(viewLifecycleOwner){
    when (it){
        Authentication.WAIT_FOR_CODE -> {
            showDialog("Enter confirmation code")
        }
        Authentication.WAIT_FOR_PASSWORD-> {
            showDialog("Enter cloud password")
        }
        Authentication.AUTHENTICATED-> {
            // request and display user data
        }
        else -> {
            showDialog("Other")
        }
    }
}

How to pass data about any changes to the main thread to display information?