QOL with last read message saving and showing the number of unread message

**Is your feature request related to a problem? Please describe.**
An important feature this app is lacking is the showing if the number of unread messages. It easy to get lost in the constant flow of messages in a group conversation.
Other messaging apps offers 2 systems:
1. First, they show you in advance the number of unread messages.
2. Secondly, they also save dynamicaly the last message read if you haven't read all the messages, thay allow you to hop back on the last message read during a next usage session of the app.

Those features will tremendously improve the user experience and create less frustration.

**Describe alternatives you've considered**
I would have use the search button and would have type the last message I remember but this app doesn't have a search button.