// dial with context and timeouts
func dialContextTimeout(ctx context.Context, network, address string, connectTimeout, timeout time.Duration) (net.Conn, error) {
dialer := net.Dialer{
Timeout: connectTimeout,
KeepAlive: 30 * time.Second,
}
c, err := dialer.DialContext(ctx, network, address)
if err != nil {
return c, err
}
return newTimeoutConn(c, timeout), nil
}