`CombineExt.Publisher.withLatestFrom`’s handling of finished events.

combine_ext_with_latest_from_finished_events.swift

import CombineExt

// Scenario one: `withLatestFrom`’s argument finishes first.

let first = PassthroughSubject<Int, Never>()
let second = PassthroughSubject<String, Never>()
var cancellables = Set<AnyCancellable>()

first
	.withLatestFrom(second) // CombineExt’s implementation
	.sink(receiveCompletion: { print($0) }, receiveValue: { print($0) })
	.store(in: &cancellables)

first.send(1)
second.send("one")
first.send(2)
second.send("two")
second.send(completion: .finished)

// Outputs:
//
// ```
// one
// ```

// Scenario two: Upstream finishes first.

// …

first.send(1)
second.send("one")
first.send(2)
second.send("two")
first.send(completion: .finished) // `first` is subbed in for `second` here.

// Outputs:
//
// ```
// one
// finished
// ```