High performance Cloud Pub/Sub client library. (NOTE) This release includes only data plane operations, publishing and pulling messages, and it is based on our gRPC beta release. (ALPHA) This library uses features that are part of an invitation-only release of the underlying Cloud Pub/Sub API. The library will generate errors unless you have access to this API. This restriction should be relaxed in the near future. Please contact [email protected] with any questions in the meantime.