Timeout Handler

[swhitty]

Adds an overload that includes a Timeout object that can be used to extend, move or cancel the timeout.

For example, the timeout can be extended by 1 second for every iteration of a sequence;

try await withThrowingTimeout(seconds: 1.0) { timeout in
  for await element in sequence {
    timeout.expire(seconds: 1.0)
    print(element)
  }
}

If possible Timeout will be marked ~Escapable in Swift 6.2, but for now a runtime assertion occurs if the object escapes the closure (via a canary and withoutActuallyEscaping)

Variants

Timeout is shared across concurrency domains — the isolation of the body closure doing the work and the Task performing and processing the timeout. Therefore, a flag is returned indicating if the timeout was in fact extended or if the timeout had already expired (and was unwinding);

let didExtend = timeout.expire(seconds: 1.0)

A deadline can also be used:

let didExtend = timeout.expire(after: .now + .seconds(1.0))

The timeout can also be cancelled indefinitely:

let didCancel = timeout.cancelExpiration()

Or expired immediately preventing any more extensions:

let didExpire = timeout.expireImmediatley()

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