code: public java.lang.String getProducerNotificationChannel() {
      java.lang.Object ref = producerNotificationChannel_;
      if (ref instanceof java.lang.String) {
        return (java.lang.String) ref;
      } else {
        com.google.protobuf.ByteString bs = 
            (com.google.protobuf.ByteString) ref;
        java.lang.String s = bs.toStringUtf8();
        producerNotificationChannel_ = s;
        return s;
      }
    }
docs: <pre>
  The full resource name of a channel used for sending notifications to the
  service producer.
  Google Service Management currently only supports
  [Google Cloud Pub/Sub](https://cloud.google.com/pubsub) as a notification
  channel. To use Google Cloud Pub/Sub as the channel, this must be the name
  of a Cloud Pub/Sub topic that uses the Cloud Pub/Sub topic name format
  documented in https://cloud.google.com/pubsub/docs/overview.
  </pre>
  
  <code>string producer_notification_channel = 7;</code>