In XPathEvaluator interface, the the method evaluate has last argument 'result' of type XPathResult. The spec says:

"result of type XPathResult

The result specifies a specific XPathResult which may be reused and returned by this method. If this is specified as nullnor the implementation cannot reuse the specified result, a new XPathResult will be constructed and returned."

What does term reuse mean in evaluate function? Does it mean that evaluate method will resuse result parameter to refine the result object or something else?