message: Add message length to rdkafka produced event
diff: @@ -256,7 +256,7 @@ export class RdkafkaProducer extends RdkafkaBase implements IProducer {
  this.handleError(err);
  } else {
  boxcar.deferred.resolve();
  - this.emit("produced", boxcarMessage, offset);
  + this.emit("produced", boxcarMessage, offset, message.length);
  }
  },
  );
  