That's it Facebook πρόσθεσε ένα χαρακτηριστικό στο Messenger. Ονομάζεται ‘instant video' and allows you to view and share a video feed with your friends while chatting.
Facebook already has video chat, and the difference with instant video is that you can send messages text as well as short video calls and not full video calls.
Facebook says:
Sometimes you just want to ask a friend's opinion about a pair of shoes you want to buy, what flavor of ice cream you should bring home, or see their reaction in a witty message when you're in a place where you can not talk live (such as arranging a meeting without hearing anyone). Instant video lets you share parts of your everyday life with the people you care most about.
So when you have the chat window open you will see the video button in the navigation bar. Tap to start a streaming video to show you what you are doing in real time.
In the meantime, your friend can choose either to just watch the video or join with his own streaming. The video will appear in a small mobile window.