@Override
    public StreamEvent find(StateEvent matchingEvent, CompiledCondition compiledCondition,
                            StreamEventCloner streamEventCloner, WindowState state) {
        return ((Operator) compiledCondition).find(matchingEvent, state.expiredEventChunk, streamEventCloner);
    }
Gets all the end timestamps of previous sessions.

@param state
@return map with the values of each previous session's end timestamp and with the key as the sesssio key
modules/siddhi-core/src/main/java/io/siddhi/core/query/processor/stream/window/SessionWindowProcessor.java