let df = DateFormatter()
df.dateStyle = .none
df.timeStyle = .long
cancellable = Timer.publish(every: 1.0, on: .main, in: .default)
    .autoconnect()
    .handleEvents(receiveOutput: { date in
        print ("Sending Timestamp \'\(df.string(from: date))\' to delay()")
    })
    .delay(for: .seconds(3), scheduler: RunLoop.main, options: .none)
    .sink(
        receiveCompletion: { print ("completion: \($0)", terminator: "\n") },
        receiveValue: { value in
            let now = Date()
            print ("At \(df.string(from: now)) received  Timestamp \'\(df.string(from: value))\' sent: \(String(format: "%.2f", now.timeIntervalSince(value))) secs ago", terminator: "\n")
        }
    )