.NET HTTP Request processor to call JSON service APIs

// See https://deliverystack.net/2021/04/02/prototype-net-class-to-invoke-contentstack-saas-headless-content-management-https-json-service-apis/

public class HttpRequestHandler
{
    public async Task<string> ProcessRequest(
        string Url,
        JObject payloadBody = null,
        string method = null)
    {
        // URL of HTTPS API call
        WebRequest request = (HttpWebRequest)WebRequest.Create(Url);

        // if caller specified an HTTP method
        if (method != null)
        {
            request.Method = method;
        }

        // if the request has a JSON payload (query), then encode it
        // and default the HTTP method if the caller did not specify
        if (payloadBody != null)
        {
            if (request.Method == null)
            {
                request.Method = "PUT"; //TODO: or default to POST?
            }

            byte[] byteArray = Encoding.UTF8.GetBytes(payloadBody.ToString());
            request.ContentLength = byteArray.Length;

            using (Stream requestStream = request.GetRequestStream())
            {
                requestStream.Write(byteArray, 0, byteArray.Length);
            }
        }
        else
        {
            // request has no JSON payload; default HTTP method
            if (request.Method == null)
            {
                request.Method = "GET";
            }
        }

        request.ContentType = "application/json";

        // user agent can be useful for statics/reporting
        request.Headers["x-user-agent"] = this.ToString();

        //TODO: vendor-specific and shouldn't be hard-coded
        request.Headers["api_key"] = "blt1119a67aaafee1ed";
        request.Headers["authorization"] = "cs38018818305e668201bc94c3";

        // call the API and return its response as a string
        using (Stream responseStream =
            ((HttpWebResponse)await request.GetResponseAsync()).GetResponseStream())
        {
            return new StreamReader(responseStream).ReadToEnd();
        }
    }
}