util/misc.go
func CheckConnection(network, ip string, port int, timeout time.Duration) bool {
	conn, _ := net.DialTimeout(network,
		net.JoinHostPort(ip, strconv.Itoa(port)), timeout)
	if conn != nil {
		conn.Close()
		return true
	}
	return false
}
func CheckConnection(network, ip string, port int, timeout time.Duration) bool {
	conn, _ := net.DialTimeout(network,
		net.JoinHostPort(ip, strconv.Itoa(port)), timeout)
	if conn != nil {
		conn.Close()
		return true
	}
	return false
}
// CheckConnection connects to the specified host on the specified port.
// If the connection is successful then return true.