fix(connection): only buffer for "open" events when calling connection helper while connecting

Author: vkarpov15

lib/connection.js

@@ -420,7 +420,7 @@ function _wrapConnHelper(fn) {
       Array.prototype.slice.call(arguments, 0, arguments.length - 1) :
       Array.prototype.slice.call(arguments);
     return utils.promiseOrCallback(cb, cb => {
-      if (this.readyState !== STATES.connected) {
+      if (this.readyState === STATES.connecting) {
         this.once('open', function() {
           fn.apply(this, argsWithoutCb.concat([cb]));
         });