pub async fn post_message(
http: &Client,
bot_token: &str,
channel_id: &str,
msg: &OutboundMsg,
) -> Result<(), SlackApiError>Expand description
POST chat.postMessage — Authorization: Bearer {bot_token}. MUST check
body.ok, not just HTTP status: Slack’s REST responses are HTTP 200 even
on many logical failures (e.g. channel_not_found, not_in_channel) —
spec §2.4.