apply method
Implementation
Future<dynamic> apply(String method, List<dynamic> params) {
var methodCompleter = Completer<dynamic>();
var newId = _currentMethodId.toString();
params = DdpClient.escapeSpecialFieldValues(params);
_sendMsgMethod(method, params, newId);
_currentMethodId++;
_methodCompleters[newId] = methodCompleter;
return methodCompleter.future;
}