title: Popup on AOD and Off Screen
body: <p>I just port my notfifcation class to Oreo and got a question how do Whatsapp and over Apps show  a small popup on AOD or if the screen is completly off ? Because the popups look the same as I think I thought that this maybe a standrd thing, but did'nt found anything about this in the notificastion section of the developer doc. This is how looks like:<a href="https://i.stack.imgur.com/j6KQ5.png" rel="nofollow noreferrer">A snapshot of a Whatsapp Msg and below another Message from a Settings dialog</a> </p>