return fmt.Errorf("Read data = %q; want nothing", data)
		}

		if err := srv.CloseWrite(); err != nil {
			return fmt.Errorf("server CloseWrite: %v", err)
		}

		// Wait for clientCloseWrite to finish, so we know we
		// tested the CloseWrite before we defer the
		// sconn.Close above, which would also cause the
		// client to unblock like CloseWrite.
		<-clientDoneChan
		return nil
	}

	return alertErr
}

var errEarlyCloseWrite = errors.New("tls: CloseWrite called before handshake complete")

// CloseWrite shuts down the writing side of the connection. It should only be
// called once the handshake has completed and does not call CloseWrite on the
// underlying connection. Most callers should just use [Conn.Close].
func (c *Conn) CloseWrite() error {
	if !c.isHandshakeComplete.Load() {