destroyAllNow also has a callback

lib/index.js

@@ -25,11 +25,12 @@ PG.prototype.end = function() {
     var pool = self.pools.all[key];
     delete self.pools.all[key];
     pool.drain(function() {
-      pool.destroyAllNow();
-      count--;
-      if(count === 0) {
-        self.emit('ended');
-      }
+      pool.destroyAllNow(function() {
+        count--;
+        if(count === 0) {
+          self.emit('ended');
+        }        
+      });
     });
   });
 };