</tt> or
    something like it.</p>

    <p>Sometimes it is necessary to have resilient APIs which can stand up to
    nearly any kind of client abuse, but there is usually a significant cost
    to this approach. For example, it usually requires that each object used
    by a client be tracked so that it can be checked for validity. If you
    need that sort of protection, it can usually be provided as a layer on
    top of a simpler API. Beware half-measures, though. An API which promises
    resilience a