code: public Object store(String correlationId, String key, Object value, long timeToLive) {
  		return value;
  	}
docs: Stores value in the cache with expiration time.
  
  @param correlationId (optional) transaction id to trace execution through
  call chain.
  @param key           a unique value key.
  @param value         a value to store.
  @param timeToLive       expiration timeout in milliseconds.
  @return a cached value stored in the cache.