The WebSocket context assumes the handshake request and response objects can be used after the handshake is performed

The WebSocket connection is initiated with an HTTP handshake request. We hook on this moment with modifyHandshake to access and cache both the HandshakeRequest and HandshakeResponse objects. The first one, HandshakeRequest gives us access to some of the HTTP request information (like headers and cookies) but more importantly to the HTTP session. The change on Jetty side is that these objects, HandshakeRequest and HandshakeResponse, are now invalidated (along with the HTTP request and response) once the handshake is done, and we end up in the WebSocket end-point. So when we try to access again the request from the cached HandshakeRequest we get an exception. The solution is to extract all the information we need from HandshakeRequest while the handshake takes place (in modifyHandshake) and to stop saving a reference to the HandshakeRequest.