Sends a JSON-RPC 2 request to invoke the given
method without expecting
parameters is the parameters for the method. This must be
Iterable (to pass parameters by position) or a
String keys (to pass parameters by name). Either way, it must be
Since this is just a notification to which the server isn't expected to send a response, it has no return value.
StateError if the client is closed when this method is called.
void sendNotification(String method, [parameters]) => _send(method, parameters);