@Override public Principal getLocalPrincipal() {
    Handshake handshake = handshake();
    return handshake != null ? handshake.localPrincipal() : null;
  }
Implement an HTTPS connection by delegating to an HTTP connection for
everything but the HTTPS-specific stuff.
gateway/platforms/servlet/src/main/java/io/apiman/gateway/platforms/servlet/connectors/ok/DelegatingHttpsURLConnection.java