message: fix: prevent attempt to publish 0 messages
diff: @@ -74,6 +74,12 @@ export abstract class MessageQueue extends EventEmitter {
  topic: topic.name,
  messages,
  };
  + if (messages.length === 0) {
  + if (typeof callback === 'function') {
  + callback(null);
  + }
  + return;
  + }
  topic.request<google.pubsub.v1.IPublishResponse>(
  {
  