Support mTLS

[rrhett]

🔖 Enhancement description

I would like to be able to specify an SSL Socket Factory on the OkHttpClient.Builder when I'm creating a Client so that I can support mutual TLS for a self-hosted instance that's behind a proxy.

Essentially, add a method like:

fun sslSocketFactory(
    sslSocketFactory: SSLSocketFactory,
    trustManager: X509TrustManager
): Client {
    http = http.newBuilder().sslSocketFactory(sslSocketFactory, trustManager).build()
    return this
}

🎤 Pitch

For self-hosted instances, there are a variety of common practices to increase security by reducing the exposure to the public internet. Two common practices are using a VPN and using mutual TLS behind a proxy. This lets apps guard access to the server by client certificates which can be issued and revoked individually, improving security to access the instance.

👀 Have you spent some time to check if this issue has been raised before?

• I checked and didn't find similar issue

🏢 Have you read the Code of Conduct?

• I have read the Code of Conduct

[rrhett]

I would like to be assigned this issue. It's a small change and I'm currently working around it via reflection which I'd prefer to remove in my app.