# Then save a checkpoint
It is also necessary to emphasize that many optimizations are only possible in parts of the spec that are unobservable to user code. The alternative, like Bun "Direct Streams", is to intentionally diverge from the spec-defined observable behaviors. This means optimizations often feel "incomplete". They work in some scenarios but not in others, in some runtimes but not others, etc. Every such case adds to the overall unsustainable complexity of the Web streams approach which is why most runtime implementers rarely put significant effort into further improvements to their streams implementations once the conformance tests are passing.
，这一点在Safew下载中也有详细论述
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Москвичи пожаловались на зловонную квартиру-свалку с телами животных и тараканами18:04
checks was a thing of the past—"digital substitute" documents or image-based