AsyncSequence is a Swift concurrency type that provides asynchronous, sequential, iterated access to its elements.
AsyncSequence is a Swift concurrency type that provides asynchronous, sequential, iterated access to its elements.
An AsyncSequence resembles the Sequence type — offering a list of values you can step through one at a time — and adds asynchronicity. An AsyncSequence may have all, some, or none of its values available when you first use it. Instead, you use await to receive values as they become available.
As with Sequence, you typically iterate through an AsyncSequence with a for await-in loop. However, because the caller must potentially wait for values, you use the await keyword.
Note, while Apple provides a variety of built-in AsyncSequence implementations (e.g. bytes(for:delegate:) in URLSession), developers can either write their own AsyncSequence or, more often, create a AsyncStream object to wrap a legacy process that emits values over time.
