using System.Security.Cryptography.X509Certificates;
using System.Text;

public class HttpClientService
{
    private readonly HttpClient _client;

    public HttpClientService()
    {
        var handler = new HttpClientHandler
        {
            ClientCertificates = { new X509Certificate2("X:\\Back\\APP Smart\\Certificado\\cert_ssl.pfx", "appsmart") }
        };
        _client = new HttpClient(handler) { DefaultRequestHeaders = { { "SOAPAction", "listarPLD" } } };
    }

    public async Task<string> EnviarRequisicaoAsync(string xmlRequest)
    {
        var content = new StringContent(xmlRequest, Encoding.UTF8, "application/json");
        var response = await _client.PostAsync("https://servicos.ccee.org.br:443/ws/prec/PLDBSv1", content);
        return await response.Content.ReadAsStringAsync();
    }
}