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var client = new HttpClient();
var request = new HttpRequestMessage(HttpMethod.Post, "https://cebheinfo.az/process/bolme");
request.Headers.Add("Cookie", "PHPSESSID=senmh133fm4qs4opqho2u5g3v5");
var content = new MultipartFormDataContent();
content.Add(new StringContent("12"), "from");
content.Add(new StringContent("gundem"), "category");
request.Content = content;
var response = await client.SendAsync(request);
response.EnsureSuccessStatusCode();
Console.WriteLine(await response.Content.ReadAsStringAsync());