pub async fn add_reaction(
    context: &Context,
    msg_id: MsgId,
    reaction: &str
) -> Result<MsgId>
Expand description

Adds given reaction to message msg_id and sends an update.

This can be used to implement advanced clients that allow reacting with multiple emojis. For a simple messenger UI, you probably want to use send_reaction() instead so reacting with a new emoji removes previous emoji at the same time.