Is a completion block considered a class field in terms of escaping or non-escaping?

In the context of Swift and iOS development, a completion block that is a class property is considered an escaping closure. This is because the block may be called after the function it was passed to has exited, for example, asynchronously.

If a completion block is passed to a function and called synchronously within it, it is non-escaping by default.

Example:

class MyClass {
    var completion: (() -> Void)? // escaping closure, as it is stored in a property

    func doSomething() {
        DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
            self.completion?() // called after a delay
        }
    }
}

Here, completion is escaping because it is called later, outside the context of the function call.