Pin feature for Signal messenger

I have been seeing different type of instant messaging​ mobile app. I use Android phone so you know what I mean by lots of messaging app.
If you have Android phone just go to Google then type instant messengers you'd see lots of options that will pop up. I don't know if it's same on other operating systems.
Well , I found this very Cool messenger. It's called signal

it look so much like whatsapp, or maybe Telegram? From the chat screen.
It's my first time using it and I see it to be very nice app. But it'd be great if it has lots of users.
Meanwhile, I have got a request !!!
My request could also be a suggestion .

Suggestion

I have tried chatting with the app , but I found a feature missing from the chats screen. This feature is the Pin Message feature.

What does the pin really do ?
** The pin helps the user to keep some particular set of chats at the top. and chats won't float down even tho they do recieve bunch of messages in seconds

advantages

The main Advantage of pining a message is to keep a very important chat or contact above every other one . When a chat is pinned it won't float down due to lots of messages.

similar request

I have taken a screenshot to show a similar request. Here's a screenshot from my WhatsApp chat. Showing pined message or contact.
This is the exact suggestion I'm talking about here. Let signal messaging app add this feature in thier next update. Thank you .