How to check TLS version of request

I have okhttp3.OkHttpClient and I make REST request using Retrofit2.

interface WebService {
    @GET("/httptwo")
    public Call<String> executeRequest();
}


//in these 2 methods I initialize server IP, SSLContext, keystore, truststore and all the stuff.
OkHttpClient client = getClient();
Retrofit retrofit = getRetrofit(client);

//make call
WebService service = retrofit.create(WebService.class);
Call<String> call = service.executeRequest();
try {
    Response<String> response = call.execute();
    String responseBody = response.body();
    System.out.println(responseBody);
} catch (Exception e) {
    e.printStackTrace();
}

I make request to my dummy Server.

@RestController
class SecureServiceController {
@RequestMapping(value = "/httptwo")
    public String httpTwoHandler() {
        String httpVersion = ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest().getProtocol();
        System.out.println("http version: " + httpVersion);
        
        return "Hello from " + httpVersion;
    }

}

As you can see, I can check version of http protocol. But how can I check version of TLS that was used?