Skill v1.0.1

version: "1.0.1"

Use [weak self] at the beginning of the closure’s capture list:

someAsyncOperation { [weak self] result in
    guard let self = self else { return }
    self.handle(result)
}

This prevents a retain cycle. Since self may become nil, you can also use optional chaining:

someAsyncOperation { [weak self] result in
    self?.handle(result)
}

Use weak if the reference can become nil. Use unowned only if self is guaranteed to outlive the closure; otherwise, unowned can crash. For delegates, use weak var delegate and constrain the protocol with AnyObject.