@Override public final void disconnect() {
    // Calling cancel() before a connection exists should have no effect.
    if (httpEngine == null) return;

    httpEngine.cancel();

    // This doesn't close the stream because doing so would require all stream
    // access to be synchronized. It's expected that the thread using the
    // connection will close its streams directly. If it doesn't, the worst
    // case is that the GzipSource's Inflater won't be released until it's
    // finalized. (This logs a warning on Android.)
  }
The most recently received TLS handshake. This will be null if we haven't
connected yet, or if the most recent connection was HTTP (and not HTTPS).
gateway/platforms/servlet/src/main/java/io/apiman/gateway/platforms/servlet/connectors/ok/HttpURLConnectionImpl.java