Dev helper for establishing SSL connections to localhost on various platformsL ios, Android, Windows, Mac

gistfile1.cs

using System.Net.Security;
using System.Net;

public class DevHttpsConnectionHelper
{
    public DevHttpsConnectionHelper(int sslPort)
    {
        SslPort = sslPort;
        DevServerRootUrl = FormattableString.Invariant($"https://{DevServerName}:{SslPort}");
        _lazyHttpClient = new Lazy<HttpClient>(() => new HttpClient(GetPlatformMessageHandler()));
    }

    public int SslPort { get; }

    public string DevServerName =>
#if WINDOWS
        "localhost";
#elif ANDROID
        "10.0.2.2";
#elif IOS || MACCATALYST
        "localhost";
#else
        throw new PlatformNotSupportedException("Only Windows and Android currently supported.");
#endif

    public string DevServerRootUrl { get; }

    private readonly Lazy<HttpClient> _lazyHttpClient;
    public HttpClient HttpClient => _lazyHttpClient.Value;

    public HttpMessageHandler GetPlatformMessageHandler()
    {
#if WINDOWS
        return null;
#elif ANDROID
        var handler = new CustomAndroidMessageHandler
        {
            ServerCertificateCustomValidationCallback = (message, cert, chain, errors) =>
        {
            if (cert != null && cert.Issuer.Equals("CN=localhost"))
            {
                return true;
            }
            return errors == SslPolicyErrors.None;
        }
        };
        return handler;
#elif IOS || MACCATALYST
var handler = new NSUrlSessionHandler
		{
			TrustOverrideForUrl = IsHttpsLocalhost,
			AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate
		};
        return handler;
#else
        throw new PlatformNotSupportedException("Only Windows and Android currently supported.");
#endif
    }

#if ANDROID
    internal sealed class CustomAndroidMessageHandler : Xamarin.Android.Net.AndroidMessageHandler
    {
        protected override Javax.Net.Ssl.IHostnameVerifier GetSSLHostnameVerifier(Javax.Net.Ssl.HttpsURLConnection connection)
            => new CustomHostnameVerifier();

        private sealed class CustomHostnameVerifier : Java.Lang.Object, Javax.Net.Ssl.IHostnameVerifier
        {
            public bool Verify(string? hostname, Javax.Net.Ssl.ISSLSession? session)
            {
                return
                    Javax.Net.Ssl.HttpsURLConnection.DefaultHostnameVerifier.Verify(hostname, session)
                    || hostname == "10.0.2.2" && session.PeerPrincipal?.Name == "CN=localhost";
            }
        }
    }
#endif

#if IOS || MACCATALYST
public static bool IsHttpsLocalhost(NSUrlSessionHandler sender, string url, Security.SecTrust trust)
	{
		if (url.StartsWith("https://localhost"))
		{
			return true;
		}

		return false;
	}	
#endif
}