How to bold title in notification?

I have got normal text, but I would like to that my string title will be display as bold.

I have tried sth like below, but it doesn't work.

           val sb: Spannable = SpannableString("Bold text")
            sb.setSpan(StyleSpan(Typeface.BOLD), 0, 3, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)

            setSmallIcon(R.color.dark_grey) // TODO: replace with an actual icon
            setContentTitle(title)
            setContentText(content)
            setStyle(NotificationCompat.InboxStyle()
                .addLine(sb)
                .setBigContentTitle(title))

You can apply Spannable to the title:

val title = "Awesome Title!"
val titleBold: Spannable = SpannableString(title)
sb.setSpan(StyleSpan(Typeface.BOLD), 0, title.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)

// ...
notificationBuilder.setContentTitle(titleBold)
// ...