Map enhancement (#220)

## Description

<!--- 
Please include a summary of the change and which issue is fixed. Please
also include relevant motivation and context.
-->

Fixes #190 

## Type of change

<!--- Please delete options that are not relevant. -->

- [x] New feature (non-breaking change which adds functionality)

## Checklist

<!--- Please delete options that are not relevant. -->

- [x] My code follows the code style of this project.
- [x] All new and existing tests passed.

Sources/RequestDL/Internals/Sources/Cache/Cache Control/Internal.CacheControl.swift

@@ -13,7 +13,7 @@ extension Internals {
 
         enum Output {
             case task(SessionTask)
-            case cache(((Internals.ResponseHead) -> Internals.AsyncStream<Internals.DataBuffer>?)?)
+            case cache((@Sendable (Internals.ResponseHead) -> Internals.AsyncStream<Internals.DataBuffer>?)?)
         }
 
         // MARK: - Internal properties
@@ -258,7 +258,7 @@ extension Internals {
         private func cacheIfNeeded(
             dataCache: DataCache,
             request: Internals.Request
-        ) async throws -> ((Internals.ResponseHead) -> Internals.AsyncStream<Internals.DataBuffer>?)? {
+        ) async throws -> (@Sendable (Internals.ResponseHead) -> Internals.AsyncStream<Internals.DataBuffer>?)? {
             guard request.isCacheEnabled else {
                 return nil
             }

Sources/RequestDL/Tasks/Sources/Modifiers/Flat Map Error/Modifiers.FlatMapError.swift

@@ -19,7 +19,7 @@ extension Modifiers {
 
         // MARK: - Internal properties
 
-        let transform: @Sendable (Error) throws -> Void
+        let transform: @Sendable (Error) async throws -> Void
 
         // MARK: - Public methods
 
@@ -34,7 +34,7 @@ extension Modifiers {
             do {
                 return try await task.result()
             } catch {
-                try transform(error)
+                try await transform(error)
                 throw error
             }
         }
@@ -65,7 +65,7 @@ extension RequestTask {
      `transform` closure.
      */
     public func flatMapError(
-        _ transform: @escaping @Sendable (Error) throws -> Void
+        _ transform: @escaping @Sendable (Error) async throws -> Void
     ) -> ModifiedRequestTask<Modifiers.FlatMapError<Element>> {
         modifier(Modifiers.FlatMapError(transform: transform))
     }
@@ -94,11 +94,11 @@ extension RequestTask {
      */
     public func flatMapError<Failure: Error>(
         _ type: Failure.Type,
-        _ transform: @escaping @Sendable (Failure) throws -> Void
+        _ transform: @escaping @Sendable (Failure) async throws -> Void
     ) -> ModifiedRequestTask<Modifiers.FlatMapError<Element>> {
         flatMapError {
             if let error = $0 as? Failure {
-                try transform(error)
+                try await transform(error)
             }
         }
     }

Sources/RequestDL/Tasks/Sources/Modifiers/Flat Map/Modifiers.FlatMap.swift

@@ -28,7 +28,7 @@ extension Modifiers {
 
         // MARK: - Internal properties
 
-        let transform: @Sendable (Result<Input, Error>) throws -> Output
+        let transform: @Sendable (Result<Input, Error>) async throws -> Output
 
         // MARK: - Public methods
 
@@ -48,7 +48,7 @@ extension Modifiers {
                 case .processed(let mapped):
                     return mapped
                 case .original(let original):
-                    return try transform(.success(original))
+                    return try await transform(.success(original))
                 }
             }
         }
@@ -59,13 +59,13 @@ extension Modifiers {
             do {
                 return .success(.original(try await task.result()))
             } catch {
-                return mapErrorIntoResult(error)
+                return await mapErrorIntoResult(error)
             }
         }
 
-        private func mapErrorIntoResult(_ error: Error) -> Result<Map, Error> {
+        private func mapErrorIntoResult(_ error: Error) async -> Result<Map, Error> {
             do {
-                return .success(.processed(try transform(.failure(error))))
+                return try await .success(.processed(transform(.failure(error))))
             } catch {
                 return .failure(error)
             }
@@ -85,7 +85,7 @@ extension RequestTask {
      - Returns: A new `RequestTask` that returns the flat-mapped element of type `NewElement`.
      */
     public func flatMap<NewElement>(
-        _ transform: @escaping @Sendable (Result<Element, Error>) throws -> NewElement
+        _ transform: @escaping @Sendable (Result<Element, Error>) async throws -> NewElement
     ) -> ModifiedRequestTask<Modifiers.FlatMap<Element, NewElement>> {
         modifier(Modifiers.FlatMap(transform: transform))
     }

Sources/RequestDL/Tasks/Sources/Modifiers/Map Error/Modifiers.MapError.swift

@@ -12,7 +12,7 @@ extension Modifiers {
 
         // MARK: - Internal properties
 
-        let transform: @Sendable (Error) throws -> Input
+        let transform: @Sendable (Error) async throws -> Input
 
         // MARK: - Public methods
 
@@ -26,7 +26,7 @@ extension Modifiers {
             do {
                 return try await task.result()
             } catch {
-                return try transform(error)
+                return try await transform(error)
             }
         }
     }
@@ -43,7 +43,7 @@ extension RequestTask {
      - Returns: The modified task with the ``Modifiers/MapError`` modifier applied.
      */
     public func mapError(
-        _ transform: @escaping @Sendable (Error) throws -> Element
+        _ transform: @escaping @Sendable (Error) async throws -> Element
     ) -> ModifiedRequestTask<Modifiers.MapError<Element>> {
         modifier(Modifiers.MapError(transform: transform))
     }

Sources/RequestDL/Tasks/Sources/Modifiers/Map/Modifiers.Map.swift

@@ -29,7 +29,7 @@ extension Modifiers {
 
         // MARK: - Internal properties
 
-        let transform: @Sendable (Input) throws -> Output
+        let transform: @Sendable (Input) async throws -> Output
 
         // MARK: - Public methods
 
@@ -41,7 +41,7 @@ extension Modifiers {
          - Throws: The error thrown by the closure, if any.
          */
         public func body(_ task: Content) async throws -> Output {
-            try transform(await task.result())
+            try await transform(task.result())
         }
     }
 }
@@ -57,7 +57,7 @@ extension RequestTask {
      - Returns: A modified `RequestTask` with the transformed element.
      */
     public func map<NewElement>(
-        _ transform: @escaping @Sendable (Element) throws -> NewElement
+        _ transform: @escaping @Sendable (Element) async throws -> NewElement
     ) -> ModifiedRequestTask<Modifiers.Map<Element, NewElement>> {
         modifier(Modifiers.Map(transform: transform))
     }

Sources/RequestDL/Tasks/Sources/Modifiers/On Status Code/Modifiers.OnStatusCode.swift

@@ -22,7 +22,7 @@ extension Modifiers {
         // MARK: - Internal properties
 
         let contains: @Sendable (StatusCode) -> Bool
-        let transform: @Sendable (Input) throws -> Void
+        let transform: @Sendable (Input) async throws -> Void
 
         // MARK: - Public methods
 
@@ -39,7 +39,7 @@ extension Modifiers {
                 return result
             }
 
-            try transform(result)
+            try await transform(result)
             return result
         }
     }
@@ -50,7 +50,7 @@ extension Modifiers {
 extension RequestTask where Element: TaskResultPrimitive {
 
     private func onStatusCode(
-        _ transform: @escaping @Sendable (Element) throws -> Void,
+        _ transform: @escaping @Sendable (Element) async throws -> Void,
         contains: @escaping @Sendable (StatusCode) -> Bool
     ) -> ModifiedRequestTask<Modifiers.OnStatusCode<Element>> {
         modifier(Modifiers.OnStatusCode(
@@ -72,7 +72,7 @@ extension RequestTask where Element: TaskResultPrimitive {
      */
     public func onStatusCode(
         _ statusCode: Range<StatusCode>,
-        _ transform: @escaping @Sendable (Element) throws -> Void
+        _ transform: @escaping @Sendable (Element) async throws -> Void
     ) -> ModifiedRequestTask<Modifiers.OnStatusCode<Element>> {
         onStatusCode(transform) {
             statusCode.contains($0)
@@ -92,7 +92,7 @@ extension RequestTask where Element: TaskResultPrimitive {
      */
     public func onStatusCode(
         _ statusCode: StatusCodeSet,
-        _ transform: @escaping @Sendable (Element) throws -> Void
+        _ transform: @escaping @Sendable (Element) async throws -> Void
     ) -> ModifiedRequestTask<Modifiers.OnStatusCode<Element>> {
         onStatusCode(transform) {
             statusCode.contains($0)
@@ -112,7 +112,7 @@ extension RequestTask where Element: TaskResultPrimitive {
      */
     public func onStatusCode(
         _ statusCode: StatusCode,
-        _ transform: @escaping @Sendable (Element) throws -> Void
+        _ transform: @escaping @Sendable (Element) async throws -> Void
     ) -> ModifiedRequestTask<Modifiers.OnStatusCode<Element>> {
         onStatusCode(transform) {
             statusCode == $0