Switched Requestable single case enumeration over to a struct instead.

Source/Request.swift

@@ -331,15 +331,12 @@ open class DataRequest: Request {
 
     // MARK: Helper Types
 
-    enum Requestable: TaskConvertible {
-        case request(URLRequest)
+    struct Requestable: TaskConvertible {
+        let urlRequest: URLRequest
 
         func task(session: URLSession, adapter: RequestAdapter?, queue: DispatchQueue) -> URLSessionTask {
-            switch self {
-            case let .request(urlRequest):
-                let urlRequest = urlRequest.adapt(using: adapter)
-                return queue.syncResult { session.dataTask(with: urlRequest) }
-            }
+            let urlRequest = self.urlRequest.adapt(using: adapter)
+            return queue.syncResult { session.dataTask(with: urlRequest) }
         }
     }
 

Source/SessionManager.swift

@@ -241,7 +241,7 @@ open class SessionManager {
         var task: URLSessionDataTask!
         queue.sync { task = self.session.dataTask(with: adaptedRequest) }
 
-        let originalTask = DataRequest.Requestable.request(originalRequest)
+        let originalTask = DataRequest.Requestable(urlRequest: originalRequest)
         let request = DataRequest(session: session, task: task, originalTask: originalTask)
 
         delegate[request.delegate.task] = request

Tests/ValidationTests.swift

@@ -242,7 +242,7 @@ class ContentTypeValidationTestCase: BaseTestCase {
 
                 let task: URLSessionDataTask = queue.syncResult { session.dataTask(with: adaptedRequest) }
 
-                let originalTask = DataRequest.Requestable.request(originalRequest)
+                let originalTask = DataRequest.Requestable(urlRequest: originalRequest)
                 let request = MockRequest(session: session, task: task, originalTask: originalTask)
 
                 delegate[request.delegate.task] = request