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Performance cuts both ways. PAYG may contribute to performance costs, because there is some overhead in supporting a runtime based composition model. ON On the other hadhand, "Just in Case" code is not being run, so that more than likely offsets the overhead. Moreover, the general principle is that establishing the ability to compose functionality (especially via mxml) is worth the overhead. For features that are opt-in via the compiler, these features may not have an extra framework cost.
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