Simplify SplPriorityQueue::serialize()

$queue = new \Zend\Stdlib\SplPriorityQueue;
for ($i=0; $i<100; $i++) {
    $queue->insert('hello'.$i, $i);
}

// Before
$time = microtime(true);
for ($i=0; $i<1000; $i++) {
    $serialized = $queue->serialize();
}
echo (microtime(true) - $time); // 0.75588607788086

// After
$time = microtime(true);
for ($i=0; $i<1000; $i++) {
    $serialized = $queue->serialize();
}
echo (microtime(true) - $time); // 0.28470015525818

src/SplPriorityQueue.php

@@ -63,24 +63,20 @@ public function toArray()
         return $array;
     }
 
+
     /**
      * Serialize
      *
      * @return string
      */
     public function serialize()
     {
-        $data = array();
-        $this->setExtractFlags(self::EXTR_BOTH);
-        while ($this->valid()) {
-            $data[] = $this->current();
-            $this->next();
-        }
-        $this->setExtractFlags(self::EXTR_DATA);
+        $clone = clone $this;
+        $clone->setExtractFlags(self::EXTR_BOTH);
 
-        // Iterating through a priority queue removes items
-        foreach ($data as $item) {
-            $this->insert($item['data'], $item['priority']);
+        $data = array();
+        foreach ($clone as $item) {
+            $data[] = $item;
         }
 
         return serialize($data);