Can a timer be scheduled to start at a real time? - swift

Question

Making a simple timer is easy. We know how to build something that fires at a certain interval. Functions and other tasks can be delayed with Dispatch Queue. Has anyone ever tried to start a function with timed precision?
I've found some documentation that shows that within the Dispatch Framework there are some structs that deal with microsecond(DispatchWallTime) and nanosecond(DispatchTime) precision. Given the assumption that a timer isn't "real-time", how can we go about firing a function precisely at a later date?
Here's a simple timer, the goal is to make the start function start at a later time but precisely at the start of a minute or a specific second.
struct ContentView: View {
#StateObject var timeManager = TimeManager()
#State var date = Date.now.formatted(.dateTime.hour().minute().second())
var body: some View {
VStack {
Text("Current Time: \(date)")
Text("Elapsed Time: \(timeManager.elapsedTime)").monospacedDigit()
HStack {
Button(action: {
timeManager.start()
}) {
Image(systemName: "play.fill")
.tint(.green)
}
Button(action: {
timeManager.stop()
}) {
Image(systemName: "stop.fill")
.tint(.red)
}
}
.font(.largeTitle)
}
}
}
class TimeManager: ObservableObject {
#Published var elapsedTime = 0
var timer = Timer()
// Make this function start at a later date/time with precision.
func start() {
timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { timer in
self.elapsedTime += 1
}
}
func stop() {
timer.invalidate()
}
}

Answer 1

I found an answer that gets to the point. It's from Paul Hudson, If anyone would like to answer this question with more depth to it or variations I'll mark it as the answer.
let date = Date().addingTimeInterval(5)
let timer = Timer(fireAt: date, interval: 0, target: self, selector: #selector(runCode), userInfo: nil, repeats: false)
RunLoop.main.add(timer, forMode: .common)
The reason I like this answer is twofold, one you can use a date. Then you can bind this to a date picker or any arbitrary date or time you choose. Two, I like it because it's built right into Swift. Please add your answer if you have a better solution. Thanks everyone!