class MyCallback : RestCallback
{
    override void OnError(int errorCode)
    {
        PrintFormat("ERROR :: code %1", errorCode);
    }
};

// ...

auto data = new JsonObject();
data.AddString("content", "this is my content");

auto cbx = new MyCallback();
auto ctx = GetRestApi().GetRestContext("http://localhost:8000/endpoint");
ctx.SetHeader("application/json");
ctx.POST(cbx, "", data.GetJson());

import asyncio
from pprint import pformat
from tornado.web import Application, RequestHandler


class WebhookHandler(RequestHandler):
    def post(self):
        print("Request received:")
        print(f"  URL: {self.request.uri}")
        print(f"  Headers:\n{pformat(dict(self.request.headers), indent=5)}")
        print(f"  Body: {self.request.body}")

        # self.set_status(204)  # uncomment to test 204 instead of 200 status code

async def main():
    app = Application([
        (r"/.*", WebhookHandler)
    ])
    app.listen(8000)
    await asyncio.Event().wait()


if __name__ == "__main__":
    asyncio.run(main())