If you want to read a file in kotlin with RX

fun getReadLinesObservable(ctx: Context, fileName: String): Observable<String> {
    return Observable
        .create { emitter:Emitter<String> ->
            val input: BufferedReader
            try {
                val open = ctx.assets.open(fileName)
                input = BufferedReader(InputStreamReader(open))
                var line = input.readLine()
                while (line != null) {
                    emitter.onNext(line)
                    line = input.readLine()
                }
                emitter.onComplete()
            } catch (e: Exception) {
                e.printStackTrace()
                emitter.onError(e)
            }
        }
}