I haven't written any golang, but why would you want a native client, when using http directly is nicely documented? I've worked with providers that worked in part of the same space, but only provided native clients, not documentation for directly using http; that was a big pain because I was porting to a language they didn't support and I had to reverse engineer the client for the language we used to use.

For me, I'm happy that they haven't changed their api in forever, I'm still using them in the same way as five years ago, I don't need to change my code.