Have you tried setting a timeout?
client.Timeout = 1000;
which would be 1 second.
I tried all of the default code and everything worked fine.
var client = new RestClient ("http://hellodadfadf");
client.Timeout = 1000;
var request = new RestRequest (String.Format ("{0}/allinfo", "198440"));
client.ExecuteAsync (request, response => {
Console.WriteLine (response.Content);
});
Also are you passing in a request at all? Hard to debug your code without the full logic.