WireGuardKit: Rename WireGuardKitSwift -> WireGuardKit

Signed-off-by: Andrej Mihajlov <and@mullvad.net>

Sources/WireGuardKit/Array+ConcurrentMap.swift

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+extension Array {
+
+    /// Returns an array containing the results of mapping the given closure over the sequence’s
+    /// elements concurrently.
+    ///
+    /// - Parameters:
+    ///   - queue: The queue for performing concurrent computations.
+    ///            If the given queue is serial, the values are mapped in a serial fashion.
+    ///            Pass `nil` to perform computations on the current queue.
+    ///   - transform: the block to perform concurrent computations over the given element.
+    /// - Returns: an array of concurrently computed values.
+    func concurrentMap<U>(queue: DispatchQueue?, _ transform: (Element) -> U) -> [U] {
+        var result = [U?](repeating: nil, count: self.count)
+        let resultQueue = DispatchQueue(label: "ConcurrentMapQueue")
+
+        let execute = queue?.sync ?? { $0() }
+
+        execute {
+            DispatchQueue.concurrentPerform(iterations: self.count) { index in
+                let value = transform(self[index])
+                resultQueue.sync {
+                    result[index] = value
+                }
+            }
+        }
+
+        return result.map { $0! }
+    }
+}