# AsyncThrowingStream.Continuation A mechanism to interface between synchronous code and an asynchronous stream. ``` struct Continuation ``` ## Overview The closure you provide to the `AsyncThrowingStream` in `init(_:bufferingPolicy:_:)` receives an instance of this type when invoked. Use this continuation to provide elements to the stream by calling one of the `yield` methods, then terminate the stream normally by calling the `finish()` method. You can also use the continuation’s `finish(throwing:)` method to terminate the stream by throwing an error. > Note: Unlike other continuations in Swift, > `AsyncThrowingStream.Continuation` supports escaping. ## Topics ### Producing Elements [`func yield(sending Element) -> AsyncThrowingStream.Continuation.YieldResult`](/documentation/Swift/AsyncThrowingStream/Continuation/yield(_:)) Resume the task awaiting the next iteration point by having it return normally from its suspension point with a given element. [`func yield(with: sending Result) -> AsyncThrowingStream.Continuation.YieldResult`](/documentation/Swift/AsyncThrowingStream/Continuation/yield(with:)) Resume the task awaiting the next iteration point by having it return normally or throw, based on a given result. [`func yield() -> AsyncThrowingStream.Continuation.YieldResult`](/documentation/Swift/AsyncThrowingStream/Continuation/yield()) Resume the task awaiting the next iteration point by having it return normally from its suspension point. [`enum YieldResult`](/documentation/Swift/AsyncThrowingStream/Continuation/YieldResult) A type that indicates the result of yielding a value to a client, by way of the continuation. ### Finishing the Stream [`func finish(throwing: Failure?)`](/documentation/Swift/AsyncThrowingStream/Continuation/finish(throwing:)) Resume the task awaiting the next iteration point by having it return nil, which signifies the end of the iteration. ### Handling Termination [`var onTermination: ((AsyncThrowingStream.Continuation.Termination) -> Void)?`](/documentation/Swift/AsyncThrowingStream/Continuation/onTermination) A callback to invoke when canceling iteration of an asynchronous stream. [`enum Termination`](/documentation/Swift/AsyncThrowingStream/Continuation/Termination) A type that indicates how the stream terminated. ### Enumerations [`enum BufferingPolicy`](/documentation/Swift/AsyncThrowingStream/Continuation/BufferingPolicy) A strategy that handles exhaustion of a buffer’s capacity. ### Default Implementations [Equatable Implementations](/documentation/Swift/AsyncThrowingStream/Continuation/Equatable-Implementations) [Hashable Implementations](/documentation/Swift/AsyncThrowingStream/Continuation/Hashable-Implementations) ## Relationships ### Conforms To [`Hashable`](/documentation/Swift/Hashable) [`Equatable`](/documentation/Swift/Equatable) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Sendable`](/documentation/Swift/Sendable) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)