feat: sendables everywhere

Asynchrone/Source/Sequences/CurrentElementAsyncSequence.swift

@@ -73,7 +73,7 @@ public actor CurrentElementAsyncSequence<Element>: AsyncSequence where Element:
 
 // MARK: Stream
 
-fileprivate struct _Stream<Element>: AsyncSequence, Sendable where Element: Sendable {
+fileprivate struct _Stream<Element>: AsyncSequence {
     private var stream: AsyncStream<Element>!
     private var continuation: AsyncStream<Element>.Continuation!
 
@@ -102,3 +102,5 @@ fileprivate struct _Stream<Element>: AsyncSequence, Sendable where Element: Send
         self.continuation.finish(with: element)
     }
 }
+
+extension _Stream: Sendable where Element: Sendable {}

Asynchrone/Source/Sequences/Fail.swift

@@ -16,7 +16,7 @@
 /// // Prints:
 /// // Error!
 /// ```
-public struct Fail<Element, Failure>: AsyncSequence where Failure: Error {
+public struct Fail<Element, Failure>: AsyncSequence, Sendable where Failure: Error {
     private let error: Failure
     private var hasThownError = false
 

Asynchrone/Source/Sequences/SequenceAsyncSequence.swift

@@ -35,33 +35,37 @@ public struct SequenceAsyncSequence<P: Sequence>: AsyncSequence {
 
     /// Creates an async iterator that emits elements of this async sequence.
     /// - Returns: An instance that conforms to `AsyncIteratorProtocol`.
-    public func makeAsyncIterator() -> SequenceAsyncSequenceIterator<P> {
+    public func makeAsyncIterator() -> Iterator {
         .init(self.sequence.makeIterator())
     }
 }
 
 extension SequenceAsyncSequence: Sendable where P: Sendable {}
 
-// MARK: SequenceAsyncSequenceIterator
+// MARK: Iterator
 
-public struct SequenceAsyncSequenceIterator<P: Sequence>: AsyncIteratorProtocol {
-    private var iterator: P.Iterator
-
-    // MARK: Initialization
-
-    public init(_ iterator: P.Iterator) {
-        self.iterator = iterator
-    }
-
-    // MARK: AsyncIteratorProtocol
-
-    /// Produces the next element in the sequence.
-    /// - Returns: The next element or `nil` if the end of the sequence is reached.
-    public mutating func next() async -> P.Element? {
-        self.iterator.next()
+extension SequenceAsyncSequence {
+    public struct Iterator: AsyncIteratorProtocol {
+        private var iterator: P.Iterator
+
+        // MARK: Initialization
+
+        init(_ iterator: P.Iterator) {
+            self.iterator = iterator
+        }
+
+        // MARK: AsyncIteratorProtocol
+
+        /// Produces the next element in the sequence.
+        /// - Returns: The next element or `nil` if the end of the sequence is reached.
+        public mutating func next() async -> P.Element? {
+            self.iterator.next()
+        }
     }
 }
 
+extension SequenceAsyncSequence.Iterator: Sendable where P.Iterator: Sendable {}
+
 // MARK: Sequence
 
 public extension Sequence {

Asynchrone/Source/Sequences/ThrowingPassthroughAsyncSequence.swift

@@ -74,3 +74,5 @@ public struct ThrowingPassthroughAsyncSequence<Element>: AsyncSequence {
         self.continuation.finish(with: element)
     }
 }
+
+extension ThrowingPassthroughAsyncSequence: Sendable where Element: Sendable {}