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The Xcode 10 release notes mention a static analyzer feature that checks for a common performance anti-pattern when using Grand Central Dispatch, involving waiting on a callback using a semaphore.1. For a function that needs to synchronously return a value from an asynchronous API, is there a more efficient solution than using a DispatchWorkItem as shown here?https://forums.developer.apple.com/message/251273#251577 2. The analyzer produces the following warning for the anti-pattern: "Waiting on a callback using a semaphore creates useless threads and is subject to priority inversion; consider using a synchronous API or changing the caller to be asynchronous"What is the priority inversion the warning refers to?At the time of this writing, the analyzer doesn’t produce a warning for the anti-pattern in Swift as it does in Objective-C.Thanks!