SSLContext constructProxySslContext() throws IOException {
        SslContextBuilder b = new SslContextBuilder();
        if (proxyCaCertificatesFile != null) {
            b.withCaCertificates(proxyCaCertificatesFile);
        } else if (proxyCaCertificates != null) {
            b.withCaCertificates(proxyCaCertificates);
        }
        return b.build();
    }
Constructs instance of {@link ai.vespa.feed.client.FeedClient} from builder configuration
vespa-feed-client/src/main/java/ai/vespa/feed/client/impl/FeedClientBuilderImpl.java