A mechanism to interface between synchronous code and an asynchronous stream.
struct ContinuationThe closure you provide to the AsyncStream 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.
import _Concurrencystruct AsyncStream<Element>An asynchronous sequence generated from a closure that calls a continuation to produce new elements.
init(_ elementType: Element.Type = Element.self, bufferingPolicy limit: AsyncStream<Element>.Continuation.BufferingPolicy = .unbounded, _ build: (AsyncStream<Element>.Continuation) -> Void) Constructs an asynchronous stream for an element type, using the specified buffering policy and element-producing closure.
@preconcurrency init(unfolding produce: @escaping () async -> Element?, onCancel: (() -> Void)? = nil) Constructs an asynchronous stream from a given element-producing closure, with an optional closure to handle cancellation.
@backDeployed(before: macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0)
static func makeStream(of elementType: Element.Type = Element.self, bufferingPolicy limit: AsyncStream<Element>.Continuation.BufferingPolicy = .unbounded) -> (stream: AsyncStream<Element>, continuation: AsyncStream<Element>.Continuation) Initializes a new AsyncStream and an Continuation.
func makeAsyncIterator() -> AsyncStream<Element>.Iterator Creates the asynchronous iterator that produces elements of this asynchronous sequence.
struct IteratorThe asynchronous iterator for iterating an asynchronous stream.
protocol SendableA thread-safe type whose values can be shared across arbitrary concurrent contexts without introducing a risk of data races. Values of the type may have no shared mutable state, or they may protect that state with a lock or by forcing it to only be accessed from a specific actor.
var onTermination: ((AsyncStream<Element>.Continuation.Termination) -> Void)? { get nonmutating set }A callback to invoke when canceling iteration of an asynchronous stream.
func finish() Resume the task awaiting the next iteration point by having it return nil, which signifies the end of the iteration.
@discardableResult func yield() -> AsyncStream<Element>.Continuation.YieldResult where Element == () Resume the task awaiting the next iteration point by having it return normally from its suspension point.
@discardableResult func yield(_ value: sending Element) -> AsyncStream<Element>.Continuation.YieldResult Resume the task awaiting the next iteration point by having it return normally from its suspension point with a given element.
@discardableResult func yield(with result: sending Result<Element, Never>) -> AsyncStream<Element>.Continuation.YieldResult Resume the task awaiting the next iteration point by having it return normally from its suspension point with a given result’s success value.
enum BufferingPolicyA strategy that handles exhaustion of a buffer’s capacity.
enum TerminationA type that indicates how the stream terminated.
enum YieldResultA type that indicates the result of yielding a value to a client, by way of the continuation.