AndrewBarba

extension Sequence {

    func mapAsync<T>(_ handler: @escaping (Element) async -> T) async -> [T] {
        return await withTaskGroup(of: (Int, T).self) { group in
            var results: [Int: T] = [:]
            for (index, item) in self.enumerated() {
                group.async { (index, await handler(item)) }
            }
            for await (index, transformed) in group {
                results[index] = transformed