Json over HTTP in Unity C#

JsonHttp.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Cysharp.Threading.Tasks;
using UnityEngine;
using UnityEngine.Networking;

namespace MyNamespace
{
    public class JsonHttp
    {
        public class HttpError : Exception
        {
            public readonly long StatusCode;

            public HttpError(long statusCode, string message) : base(message)
            {
                StatusCode = statusCode;
            }
            public HttpError(long statusCode, string message, Exception baseException) : base(message, baseException)
            {
                StatusCode = statusCode;
            }
            override public string ToString()
            {
                return $"HttpError(statusCode: {StatusCode}, message: {Message})";
            }
        }

        private readonly Uri _baseUri;

        public JsonHttp(string baseUri)
        {
            this._baseUri = new Uri(baseUri);
        }

        public async Task<Result<T, HttpError>> Get<T>(string path, Dictionary<string, string> query = null, Dictionary<string, string> headers = null, int timeoutSec = 3)
        {
            var urlParameter = query != null ? $"?{String.Join("&", query.Select(pair => pair.Key + "=" + pair.Value))}" : "";
            var url = new Uri(_baseUri, $"{path}{urlParameter}");
            Debug.Log($"GET url: {url}, query: {query}");
            var request = UnityWebRequest.Get(url);
            return await ProcessJsonRequest<T>(request, headers, timeoutSec);
        }

        public async Task<Result<T, HttpError>> Post<T>(string path, object requestBody, Dictionary<string, string> headers = null, int timeoutSec = 3)
        {
            var url = new Uri(_baseUri, path);
            var body = JsonUtility.ToJson(requestBody);
            Debug.Log($"POST url: {url}, body: {body}");
            var request = new UnityWebRequest(url, "POST");
            request.uploadHandler = new UploadHandlerRaw(Encoding.UTF8.GetBytes(body));
            request.downloadHandler = new DownloadHandlerBuffer();
            return await ProcessJsonRequest<T>(request, headers, timeoutSec);
        }

        private async Task<Result<T, HttpError>> ProcessJsonRequest<T>(UnityWebRequest request, Dictionary<string, string> headers, int timeoutSec)
        {
            request.timeout = timeoutSec;

            request.SetRequestHeader("Content-Type", "application/json");
            request.SetRequestHeader("Accept", "application/json");

            if (headers != null)
            {
                foreach (var entry in headers)
                {
                    request.SetRequestHeader(entry.Key, entry.Value);
                }
            }

            try
            {
                await request.SendWebRequest().WithCancellation(CancellationToken.None);

                var text = request.downloadHandler.text;
                Debug.Log($"result: {request.result}, responseCode: {request.responseCode}, body: {text}, error: {request.error}");

                // Consider the request succeeded only when it gets 200-399 HTTP status code
                if (request.result == UnityWebRequest.Result.Success && request.responseCode >= 200 && request.responseCode < 400)
                {
                    var body = JsonUtility.FromJson<T>(text);
                    return Result<T, HttpError>.Succeeded(body);
                }
                else
                {
                    return Result<T, HttpError>.Failed(new HttpError(request.responseCode, request.error.Length > 0 ? request.error : text));
                }
            }
            catch (Exception e)
            {
                return Result<T, HttpError>.Failed(new HttpError(request.responseCode, $"ProcessJsonRequest failed due to {e}"));
            }
        }
    }
}

Result type defined here https://gist.github.com/petitviolet/d29d7cd4d3f967ebda06a7b429d05070