Notification.kt

with(builder) {
            setContentTitle(
                context.resources.getString(
                    R.string.message_from,
                    simpleMessage.sender
                )
            )
            setSmallIcon(R.drawable.ic_stat_notification)
            setCategory(android.app.Notification.CATEGORY_MESSAGE)
            setContentIntent(
                PendingIntent.getActivity(
                    context,
                    REQUEST_CONTENT,
                    Intent(context, MainActivity3::class.java)
                        .setAction(Intent.ACTION_VIEW)
                        .setData(contentUri),
                    PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_MUTABLE
                )
            )
            setShowWhen(true)
        }