NewMessageCreationWorker.kt

class NewMessageCreationWorker(var context: Context, params: WorkerParameters) : Worker(context, params) {

    private newMessageDb: newMessageDb = ... // from dependency injection

    override fun doWork(): Result {
        var jobId = inputData.getString(NewMessage.KEY_JOB_ID)?.run { this } ?: ""
        var newMessage = newMessageDb.find(jobId)
        return newMessage?.run {
            val postMesageResponse = postMessage(this)
            if (response.isSuccessful) {
                startUploadMediaFile(this, response)
                Result.SUCCESS
            } else {
                Result.RETRY
            }
        } ?: kotlin.run { Result.FAILURE }
    }

    private fun postMessage(newMessage: NewMessage): Response<Void> {
        ... // send POST /message request and return response
    }

    private fun startUploadMediaFile(newMessage: NewMessage, response: Response<Void>) {
        val uploadUrl: String = ... // parse media upload link from response
        FileUploader.submitMediaUploadWork(newMessage, uploadUrl)
    }
}