Go x/crypto/ssh -- How to establish ssh connection to private instance over a bastion node

I want to implement this scenario: On AWS, I have a VPC, in which it is deployed a public and private subnet. In the public subnet, I have a "bastion" instance, while in private subnet, there is one node running some services(AKA "service instance"). By using *nux ssh command, I can do things like this to connect to the "service instance" from my local laptop:

ssh -t -o ProxyCommand="ssh -i <key> ubuntu@<bastion-ip> nc %h %p" -i <key> ubuntu@<service-instance-ip>

I have a Go program, and want to do the following things:

1. ssh connect to the "service instance" from "local laptop" over the "bastion"
2. use the connection session to run some commands (e.g. "ls -l")
3. upload files from "local laptop" to "service instance"

I've tried but not able to implement the same process as doing

ssh -t -o ProxyCommand="ssh -i <key> ubuntu@<bastion-ip> nc %h %p" -i <key> ubuntu@<service-instance-ip>

Could anyone help to show me an example? Thanks!

BTW, I found this: https://github.com/golang/go/issues/6223, which means it is definately able to do that, right?