var client = new RestClient("https://api.example.com"); client.AddDefaultParameter("api_key", "myapikey");
var client = new RestClient("https://api.example.com"); client.AddDefaultParameter("Authorization", "Bearer mytoken", ParameterType.HttpHeader);In this example, the AddDefaultParameter method is used to add the "Authorization" header with the value "Bearer mytoken" to every request made using the RestClient instance. Package Library: RestSharp (https://www.nuget.org/packages/RestSharp/)