Согласно названию вопроса. Вот простое повторение; . Net Консольное приложение Core 3.1:
class Program
{
static async Task Main(string[] args)
{
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("https://www.bitmex.com/api/v1/");
try
{
HttpResponseMessage response = await client.GetAsync("orderbook/L2?symbol=XBT&depth=0");
// TODO: Inspect why it takes ~10s for breakpoint to go from
// previous line to next while debugging,
// whereas in Postman it takes ~2s.
if (response.IsSuccessStatusCode)