...we’re making the beta release of Google Cloud Pub/Sub available today, as a way to connect applications and services, whether they're hosted on Google Cloud Platform or on-premises. The Google Cloud Pub/Sub API provides:

Scale: offering all customers, by default, up to 10,000 topics and 10,000 messages per second

Global deployment: dedicated resources in every Google Cloud Platform region enhance availability without increasing latency

Performance: sub-second notification even when tested at over 1 million messages per second
Google Releases Cloud Pub/Sub Connecting Applications and Data Streams [googlecloudplatform.blogspot.com]

You can activate Google Cloud Pub/Sub today from the APIs & auth section of the Google Developers Console and monitor key metrics with Google Cloud Monitoring dashboards.