Покопавшись немного разобрался. На благо всех:
private bool FinancialStatement(string symbol, string statement, string period)
{
var target = $"{BASE_URL}{symbol}/financials-data?period_type={period}&statement_type={statement}&order_type=latest_left&is_pro=True";
var client = new RestClient(target);
client.Timeout = -1;
var request = new RestRequest(Method.GET);
request.AddHeader("Cookie", MACHINE_COOKIE);
IRestResponse response = client.Execute(request);
dynamic responseObj;
try
{
responseObj = JsonConvert.DeserializeObject(response.Content);
}
catch (Exception)
{
return false;
}
return response.IsSuccessful;
}