概念的には↓のように考えれば合ってる？ final class Counter { private let queue: DiqpatchQueue = ... // Serial Queue private var _count: Int = 0 var count: Int { get async { withCheckedContinuation { continuation in queue.async { continuation.resume(returning: _count) } } } } private func _countUp(_ amount: Int) -> Int { count += amound return count } func countUp(_ amount: Int) async -> Int { withCheckedContinuation { continuation in queue.async { continuation.returning(returning: _countUp(amount)) } } } private func _countUp() -> Int { _countUp(1) } func countUp() async -> Int { withCheckedContinuation { continuation in queue.async { continuation.resume(returning: _countUp()) } } } } (edited)
