Function deltachat::reaction::set_msg_reaction

pub(crate) async fn set_msg_reaction(
    context: &Context,
    in_reply_to: &str,
    chat_id: ChatId,
    contact_id: ContactId,
    timestamp: i64,
    reaction: Reaction
) -> Result<()>

Updates reaction of contact_id on the message with in_reply_to Message-ID. If no such message is found in the database, reaction is ignored.

reaction is a space-separated string of emojis. It can be empty if contact wants to remove all reactions.