using RestSharp;


var options = new RestClientOptions("https://api.sandbox.{id}.gr4vy.app/webhook-subscriptions");
var client = new RestClient(options);
var request = new RestRequest("");
request.AddHeader("Authorization", "Bearer <token>");
request.AddJsonBody("{\n  \"active\": true,\n  \"url\": \"https://example.com/webhooks\",\n  \"authentication\": {\n    \"kind\": \"basic\",\n    \"username\": \"username\",\n    \"password\": \"password\"\n  }\n}", false);
var response = await client.PostAsync(request);

Console.WriteLine("{0}", response.Content);

{
  "type": "webhook-subscription",
  "id": "8fd77b13-a5e3-43de-bd54-26a8a714ac18",
  "merchant_account_id": "default",
  "active": true,
  "url": "https://example.com/webhooks",
  "authentication": {
    "kind": "basic",
    "username": "username",
    "password": "password"
  },
  "secret": "234567890abcdef1234567890abcdef",
  "rotating": false
}