             return
         }
         
+        let stopwatch = MXStopwatch()
+        
         mergeQueue.async {
             var result: MXSyncResponse?
             var syncToken: String?

        // Merge the new sync response to the old one
        var dictionary = NSDictionary(dictionary: oldSyncResponse.jsonDictionary())
        dictionary = dictionary + NSDictionary(dictionary: newSyncResponse.jsonDictionary())
        
        return MXSyncResponse(fromJSON: dictionary as? [AnyHashable : Any])
    }

                }
            }
            
            MXLog.debug("[MXSyncResponseStoreManager] mergedSyncResponse: merging \(responseIds.count) sync responses lasted \(stopwatch.readable())")
            
            if let result = result {
                DispatchQueue.main.async {
                    completion(MXCachedSyncResponse(syncToken: syncToken,
