message: flushing data when authenticating to avoid tls stall
  refs
diff: @@ -153,22 +153,24 @@ pub async fn startup<
  }
  let response = session_authenticator.initial_response();
  - transport
  - .lock()
  - .await
  - .write_all(Frame::new_req_auth_response(response).as_bytes().as_slice())
  + {
  + let mut lock = transport.lock().await;
  +
  + lock.write_all(Frame::new_req_auth_response(response).as_bytes().as_slice())
  .await?;
  + lock.flush().await?;
  + }
  loop {
  let frame = parse_frame(transport, compression).await?;
  match frame.body()? {
  ResponseBody::AuthChallenge(challenge) => {
  let response = session_authenticator.evaluate_challenge(challenge.data)?;
  - transport
  - .lock()
  - .await
  - .write_all(Frame::new_req_auth_response(response).as_bytes().as_slice())
  + let mut lock = transport.lock().await;
  +
  + lock.write_all(Frame::new_req_auth_response(response).as_bytes().as_slice())
  .await?;
  + lock.flush().await?;
  }
  ResponseBody::AuthSuccess(..) => break,
  _ => return Err(format!("Unexpected auth response: {:?}", frame.opcode).into()),
  