support priority queues

Author: Devon Weller

src/Queue/RabbitMQQueue.php

@@ -85,6 +85,11 @@ public function pushRaw($payload, $queueName = null, array $options = [])
                 $message->setProperty(RabbitMQJob::ATTEMPT_COUNT_HEADERS_KEY, $options['attempts']);
             }
 
+            // set priority
+            if (isset($options['priority']) && $options['priority'] > 0) {
+                $message->setPriority($options['priority']);
+            }
+
             $producer = $this->context->createProducer();
             if (isset($options['delay']) && $options['delay'] > 0) {
                 $producer->setDeliveryDelay($options['delay'] * 1000);