close() function on both iterators, to avoid NativePdoIterator connection leaks.

Author: imota

src/Iterator.php

@@ -4,4 +4,5 @@
 
 interface Iterator extends \Countable, \Traversable
 {
+    public function close();
 }

src/LimitIterator.php

@@ -180,4 +180,9 @@ protected function loadCount()
             ->fetch(\PDO::FETCH_ASSOC);
         $this->rowCount = $row['FOUND_ROWS'];
     }
+
+    public function close()
+    {
+        $this->pdo = null;
+    }
 }

src/NativePDOIterator.php

@@ -14,4 +14,10 @@ public function count()
     {
         return $this->rowCount();
     }
+
+    public function close()
+    {
+        parent::closeCursor();
+        $this->pdo = null;
+    }
 }