The first thing you need to consider is why you want to bother with batching
Batching is not going to save you quota, in some case it will increase the likly hood that you will get a flooding error. All batching saves you is the number of HTTP calls.
You're limited to 50 calls in a single batch request and they must all be to the same authorized user. So unless you are planning on inserting a large number of events to a single users calendar there is really no reason to work out batching.
That being said from what i can see the google-apis-go-client does not support batching and they dont intend to add it. Which would mean that if you do in fact want to add batching you will need to check the first link i posted and code this manually yourself.