How can I get tx_hash from EventData::Tx ?

[theanh098]

    let (client, driver) = WebSocketClient::new(WSS_URL).await.unwrap();

    let driver_handle = tokio::spawn(async move { driver.run().await });

    let mut subs = client.subscribe(query).await.unwrap();

    while let Some(res) = subs.next().await {
        let event = res.unwrap();

        if let EventData::Tx { tx_result } = event.data {
            tx_handler(db, cosmos_client, tx_result)
                .await
                .unwrap_or_else(|error| {
                    eprintln!(
                        "{:#?}>> Unxpected error when hanlde tx event: {:#?}",
                        ctx, error
                    );
                });
        }
    }

    client.close().unwrap();

How to get transaction hash from tx_result ?