using System;

using System.IO;

using System.Text.Json;

using System.Threading.Tasks;

using System.Net.Http;

public class Program

{

    public static async Task Main()

    {

        using var client = new HttpClient();

        var model = new 

        {

            userId= 1,

            id= 1,

            title= "foo",

            body= "bar"

        };

        using var modelStream = new MemoryStream();

        await JsonSerializer.SerializeAsync(modelStream, model);

        modelStream.Position = 0;

        modelStream.Seek(0, SeekOrigin.Begin);

        await modelStream.FlushAsync();

        using var requestContent = new StreamContent(modelStream);

        using var response = await client.PutAsync("https://jsonplaceholder.typicode.com/posts/1", requestContent);

        var result = await JsonSerializer.DeserializeAsync<JsonElement>(await response.Content.ReadAsStreamAsync());

        Console.WriteLine(result);

    }

}