title: how to add protobuf file for topic in gcloud pubsub?
body: <p>In google cloud's pubsub, I can see that on creating a new topic, I have to create a new message. Can I store a protobuf file there instead of having to write the whole structure of message in key-value pairs? For the protobuf code that shall be written, I mean <a href="https://github.com/googleapis/googleapis/blob/master/google/pubsub/v1/pubsub.proto" rel="nofollow noreferrer">this</a>. If the protobuf isnt meant to be put on the gcloud pubsub, how can I use it with grpc client?</p>