Introduce configuration to the loader to allow URLSession configuration

This set up allows for future configuration of the loader and keeps the PathConfiguration.Source enum focused on the source of the config file rather than the specific method of obtaining the file.

Source/Path Configuration/PathConfiguration.swift

@@ -7,6 +7,16 @@ public protocol PathConfigurationDelegate: AnyObject {
     func pathConfigurationDidUpdate()
 }
 
+public struct PathConfigurationLoaderOptions {
+    public init(urlSessionConfiguration: URLSessionConfiguration? = nil) {
+        self.urlSessionConfiguration = urlSessionConfiguration
+    }
+
+    /// If present, the ``PathConfigurationLoader`` will initialize a new `URLSession` with
+    /// this configuration to make its network request
+    public let urlSessionConfiguration: URLSessionConfiguration?
+}
+
 public final class PathConfiguration {
     public weak var delegate: PathConfigurationDelegate?
 
@@ -26,8 +36,9 @@ public final class PathConfiguration {
 
     /// Multiple sources will be loaded in order
     /// Remote sources should be last since they're loaded async
-    public init(sources: [Source] = []) {
+    public init(sources: [Source] = [], options: PathConfigurationLoaderOptions? = nil) {
         self.sources = sources
+        self.options = options
         load()
     }
 
@@ -63,11 +74,13 @@ public final class PathConfiguration {
     }
 
     // MARK: - Loading
+
+    private let options: PathConfigurationLoaderOptions?
 
     private var loader: PathConfigurationLoader?
-
+    
     private func load() {
-        loader = PathConfigurationLoader(sources: sources)
+        loader = PathConfigurationLoader(sources: sources, options: options)
         loader?.load { [weak self] config in
             self?.update(with: config)
         }
@@ -92,6 +105,5 @@ extension PathConfiguration {
         case data(Data)
         case file(URL)
         case server(URL)
-        case serverRequest(URLRequest)
     }
 }

Source/Path Configuration/PathConfigurationLoader.swift

@@ -6,10 +6,12 @@ final class PathConfigurationLoader {
     private let cacheDirectory = "Turbo"
     private let configurationCacheFilename = "path-configuration.json"
     private let sources: [PathConfiguration.Source]
+    private let options: PathConfigurationLoaderOptions?
     private var completionHandler: PathConfigurationLoaderCompletionHandler?
 
-    init(sources: [PathConfiguration.Source]) {
+    init(sources: [PathConfiguration.Source], options: PathConfigurationLoaderOptions? = nil) {
         self.sources = sources
+        self.options = options
     }
 
     func load(then completion: @escaping PathConfigurationLoaderCompletionHandler) {
@@ -23,8 +25,6 @@ final class PathConfigurationLoader {
                 loadFile(url)
             case .server(let url):
                 download(from: url)
-            case .serverRequest(let request):
-                download(with: request)
             }
         }
     }
@@ -34,17 +34,14 @@ final class PathConfigurationLoader {
     private func download(from url: URL) {
         precondition(!url.isFileURL, "URL provided for server is a file url")
 
-        download(with: URLRequest(url: url))
-    }
-
-    private func download(with request: URLRequest) {
-
         // Immediately load most recent cached version if available
         if let data = cachedData() {
             loadData(data)
         }
 
-        URLSession.shared.dataTask(with: request) { [weak self] data, response, error in
+        let session = options?.urlSessionConfiguration.map { URLSession(configuration: $0) } ?? URLSession.shared
+
+        session.dataTask(with: url) { [weak self] data, response, error in
             guard let data = data,
                 let httpResponse = response as? HTTPURLResponse,
                 httpResponse.statusCode == 200