Kotlin: sms receiver and rx bus in Android

SmsReceiver.kt

data class Sms(val phone: String, val text: String)

object SmsBus {
    private val bus by lazy { PublishSubject.create<Sms>() }

    fun incomingSms(): Observable<Sms> = bus
    fun postSms(sms: Sms) = bus.onNext(sms)
}


class SmsReceiver: BroadcastReceiver() {

    override fun onReceive(context: Context?, intent: Intent?) {
        val pdu = (intent?.extras?.get("pdus") as? Array<Any>)?.get(0) as? ByteArray
        pdu?.let {
            val message = SmsMessage.createFromPdu(it)
            val sms = Sms(
                    phone = message.displayOriginatingAddress,
                    text = message.displayMessageBody
            )
            SmsBus.postSms(sms)
        }
    }
}