@Override
        public Map<String, Object> snapshot() {
            Map<String, Object> state = new HashMap<>();
            state.put("sessionMap", sessionMap);
            state.put("sessionContainer", sessionContainer);
            state.put("expiredEventChunk", expiredEventChunk);
            return state;
        }
Collection used to manage session windows.

@param <E> sub types of ComplexEvent such as StreamEvent and StateEvent.
modules/siddhi-core/src/main/java/io/siddhi/core/query/processor/stream/window/SessionWindowProcessor.java