Does Google discourage use of 3rd party Go drivers for cloud sql using?

According to this

There is a Go library for Cloud SQL.

Google Cloud SQL on App Engine:
user@cloudsql(project-id:instance-name)/dbname

But according the GAE site, you can (maybe should?) use only java or python to connect to Cloud SQL: https://developers.google.com/cloud-sql/faq#languages

Can I use languages other than Java or Python?
    Only Java and Python are supported for Google Cloud SQL.

I'm determining if GAE is a good fit for my Go application. Is Google discouraging the use of 3rd party libraries to connect to Cloud SQL?

Not being able to use Cloud SQL would be a deal breaker for me and will have me looking for another platform to host my Go application.

> Using Google Cloud SQL with App Engine Go SDK
>
> This document describes how to use Google Cloud SQL instances with the
> App Engine Go SDK.
>
> Cloud SQL with Go-MySQL-Driver
>
> We would like to add support for Cloud SQL to
> github.com/go-sql-driver/mysql.
>
> There shouldn't be much to do. The appengine/cloudsql package 1
> provides a Dial function that takes a CloudSQL instance name and
> returns a net.Conn; you just have to arrange for your mysql driver to
> call that (or have some way of taking a net.Conn).
>
> You could follow what we did for ziutek's mymysql package 2.

Why do you think you have will have a problem?

I belive you can use 3rd packages, here is the document in Go specific App Engine API:
https://developers.google.com/appengine/docs/go/cloud-sql/reference

> Applications should use this package through database/sql: Select a
> pure Go MySQL driver that supports this package, and use sql.Open with
> protocol "cloudsql" and an address of the CloudSQL instance. The exact
> format of the second argument to sql.Open is driver-dependent; consult
> the driver's documentation for details.

import "database/sql"
import _ "<some mysql package>"

So I think "<some mysql package>" can be https://github.com/go-sql-driver/mysql