Checks if a method has a response handler registered for it. Used to determine
if the server should send a request or a notification to the client (if the
method has a response handler, then the server will expect a response and thus
send a request instead of a notification).
Checks if a method has a response handler registered for it. Used to determine if the server should send a request or a notification to the client (if the method has a response handler, then the server will expect a response and thus send a request instead of a notification).