reads json file with array of objects and post them in batches (example: post 6 requests in parallel, each time)

post_json_array.cs

using MoreLinq;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp3
{
    static class Program
    {
        private static HttpClient _client = new HttpClient();
        private static string internalPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);

        // API
        public const string hostAddress = "http://foo.com.br";
        public const string endpoint = "/minha-api/api/v2/clients";
        public const string token = "TOKEN";

        // FILES
        public const string sourceFileName = "file.json";
        public const string errorFileName = "errors.txt";
 
        // BATCH
        public const int batchSize = 6;

        static async Task Main(string[] _)
        {
            _client.BaseAddress = new Uri(hostAddress);
            _client.DefaultRequestHeaders.Add("Authorization", token);

            var orders = await GetOrders();
            var counter = 0;
            var erroStream = new StreamWriter(Path.Combine(internalPath, errorFileName));

            foreach (var sendOrderRequest in orders.Batch(batchSize))
            {
                var tasks = sendOrderRequest.Select(x => Send(x));
                var responses = await Task.WhenAll(tasks);

                for (var i = 0; i < responses.Length; i++)
                {
                    if (responses[i].StatusCode == HttpStatusCode.Created)
                    {
                        continue;
                    }

                    var obj = new
                    {
                        HttpStatus = responses[i].StatusCode,
                        Body = await responses[i].Content?.ReadAsStringAsync(),
                        Request = sendOrderRequest.ElementAt(i),
                    };

                    var log = JsonConvert.SerializeObject(obj) + "\n\n\n";

                    await erroStream.WriteLineAsync(log);
                    await erroStream.FlushAsync();
                }

                counter += responses.Length;
                Console.WriteLine(counter);
            }

            Console.WriteLine("Finished");
        }

        private static async Task<HttpResponseMessage> Send(string sendOrderRequest)
        {
            var httpRequest = new HttpRequestMessage()
            {
                Method = HttpMethod.Post,
                RequestUri = new Uri(endpoint, UriKind.Relative),
                Content = new StringContent(
                    sendOrderRequest,
                    Encoding.UTF8,
                    "application/json")
            };

            var response = await _client.SendAsync(httpRequest);
            return response;
        }

        private static async Task<IEnumerable<string>> GetOrders()
        {
            var fullMappingPath = Path.Combine(internalPath, sourceFileName);

            using var reader = new StreamReader(fullMappingPath);
            var fileContent = await reader.ReadToEndAsync();

            JArray array = JArray.Parse(fileContent);

            return array.Children<JObject>().Select(x => x.ToString());
        }
    }
}