Blocking Call In Async (ARCH9028)

Key swift.async.blocking-call-in-async · Severity error · Category async

Flags sleep(), Thread.sleep and usleep inside async functions - they block a cooperative-pool thread instead of suspending.

Incorrect

func poll() async {
    sleep(1)
}

Correct

func poll() async throws {
    try await Task.sleep(for: .seconds(1))
}

Fix

Use Task.sleep.