Override TLS mode

[yschimke]

ConnectionSpec.supportsTlsExtensions is deprecated. However it is the only mechanism to stop OkHttp overriding the SSLParameters after a custom sslSocketFactory has made changes.

We should continue to deprecate supportsTlsExtensions, but allow the same functionality via a similar feature, in which OkHttp would expect clients to completely own the configuration of TLS.

See where we use the current flag to avoid setting ALPN

okhttp/okhttp/src/jvmMain/kotlin/okhttp3/internal/connection/ConnectPlan.kt

Line 331 in ff8da5f

Platform.get().configureTlsExtensions(sslSocket, address.url.host, address.protocols)

and an example of the configuration done

https://github.com/square/okhttp/blob/ff8da5fa0d7735f012105317b03571a776efa4fc/okhttp/src/jvmMain/kotlin/okhttp3/internal/platform/android/Android10SocketAdapter.kt