HttpUrlConnection ignores proxy on Android < KitKat - xamarin

Question

I'm using a library that uses a Proxy on http requests to add security. The problem is that it works perfectly on Android >= KitKat, but in JellyBean it does not go through the proxy.
Do you know if proxy is supported using AndroidClientHandler in that version? I know that TLS 1.2+ is not supported using AndroidClientHandler pre Lollipop, but I need that handler (in fact I inherit from AndroidClientHandler to bypass SSL verification because the proxy takes care of that and it is needed by the library) to configure some things of how the proxy works.
MyCustomMessageHandler implementation:
public class MyCustomMessageHandler : AndroidClientHandler
{
public override bool SupportsProxy => true;
protected override SSLSocketFactory ConfigureCustomSSLSocketFactory(HttpsURLConnection connection)
{
return this.GetBypassVerificationSSLSocketFactory();
}
protected override IHostnameVerifier GetSSLHostnameVerifier(HttpsURLConnection connection)
{
return new CustomHostnameVerifier();
}
protected override async Task SetupRequest(HttpRequestMessage request, HttpURLConnection conn)
{
this.HandleCustomPreAuthentication(conn);
await base.SetupRequest(request, conn);
}
private void HandleCustomPreAuthentication(HttpURLConnection conn)
{
var proxyAuth = "MyUsername" + ":" + "MyPassword";
var encodedProxyAuth = Base64.EncodeToString(Encoding.UTF8.GetBytes(proxyAuth), Base64Flags.Default);
conn.SetRequestProperty("Proxy-Authorization", encodedProxyAuth);
}
private SSLSocketFactory GetBypassVerificationSSLSocketFactory()
{
SSLContext sslContext;
try
{
sslContext = SSLContext.GetInstance("SSL");
sslContext.Init(new IKeyManager[0], new ITrustManager[] { new X509TrustManager() }, new SecureRandom());
return sslContext.SocketFactory;
}
catch (GeneralSecurityException e)
{
throw new RuntimeException(e);
}
}
}
public class CustomHostnameVerifier : Java.Lang.Object, IHostnameVerifier
{
public bool Verify(string hostname, ISSLSession session) => true;
}
public class X509TrustManager : Java.Lang.Object, IX509TrustManager
{
public void CheckClientTrusted(X509Certificate[] chain, string authType)
{
}
public void CheckServerTrusted(X509Certificate[] chain, string authType)
{
}
public X509Certificate[] GetAcceptedIssuers()
{
return new X509Certificate[0];
}
}
I've already tried configuring the proxy using Managed client but it does not work as expected; that's why I chose AndroidClientHandler
I infer it is not going through the proxy because capturing packets I realized that < KitKat it sends the requests over Http while >= KitKat they are all over TCP or TLSv1.2 and the proxy is an https url.