"Editing" icon for messages

In the same vein as the "Typing..." message displayed at the bottom of the chat area, it would be helpful for conversational flow if there was an icon displayed next to messages that a user has started editing, to let other users know that the message may change soon. Perhaps by the timestamp:
<User> Today at 8:19 AM - Currently Editing :pencil emoji:
or
8:19 AM :pencil emoji: // for continuation messages