SwiftConcurrencyPublisher.swift

public struct SwiftConcurrencyPublisher<Output: Sendable, Failure: Sendable & Error> : Publisher {
    private let subject: Publishers.HandleEvents<PassthroughSubject<Output, Failure>>

    public init(body: @Sendable @escaping () async -> Result<Output, Failure>) {
        let subject = PassthroughSubject<Output, Failure>()
        let task = Task {
            switch await body() {
            case .success(let success):
                subject.send(success)
                subject.send(completion: .finished)
            case .failure(let failure):
                subject.send(completion: .failure(failure))
            }
        }
        self.subject = subject.handleEvents(receiveCancel: { task.cancel() })
    }

    public func receive<S>(subscriber: S) where S : Subscriber, Failure == S.Failure, Output == S.Input {
        subject.receive(subscriber: subscriber)
    }
}