NostrClient.cs

using System.Net.WebSockets;
using System.Text;

Uri uri = new("wss://yabu.me/");

using ClientWebSocket ws = new();
await ws.ConnectAsync(uri, default);

var req = "[\"REQ\", \"_\", {\"kinds\": [1], \"limit\": 10}]";
Console.WriteLine("< " + req);
await ws.SendAsync(Encoding.UTF8.GetBytes(req), WebSocketMessageType.Text, true, default);

var buffer = new byte[1024];
while (true)
{
    ArraySegment<byte> segment = new(buffer);
    var result = await ws.ReceiveAsync(segment, default);

    if (result.MessageType == WebSocketMessageType.Close)
    {
        await ws.CloseAsync(WebSocketCloseStatus.NormalClosure, "OK", default);
        return;
    }

    var count = result.Count;
    while (!result.EndOfMessage)
    {
        if (count >= buffer.Length)
        {
            await ws.CloseAsync(WebSocketCloseStatus.NormalClosure, "That's too long", default);
            return;
        }

        segment = new ArraySegment<byte>(buffer, count, buffer.Length - count);
        result = await ws.ReceiveAsync(segment, default);
        count += result.Count;
    }

    var message = Encoding.UTF8.GetString(buffer, 0, count);
    Console.WriteLine("> " + message);
}