Exercise 2: Adding a Real OSSignposter Interval Around syncWithServer() — Possible Solution
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import os

let signposter = OSSignposter(logHandle: OSLog(subsystem: "com.osztromok.taskflow", category: "sync"))

@MainActor
@Observable
final class TaskListViewModel {
    var tasks: [Task] = []
    var isSyncing = false

    func syncWithServer() async {
        let interval = signposter.beginInterval("Sync With Server")
        defer { signposter.endInterval("Sync With Server", interval) }

        isSyncing = true
        defer { isSyncing = false }

        do {
            let (data, _) = try await URLSession.shared.data(from: syncURL)
            let dtos = try JSONDecoder().decode([TaskDTO].self, from: data)
            tasks = dtos.map { $0.toTask() }
        } catch {
            // real error handling from Architecture & Data's own capstone, unchanged
        }
    }
}

HOW IT WORKS: The chapter's own established pattern wraps the real work
- everything syncWithServer() actually does - between a
signposter.beginInterval("Sync With Server") call and a matching
signposter.endInterval("Sync With Server", interval) call, using
Swift's own defer keyword so the interval is guaranteed to close no
matter which real path the function takes, including the catch branch
if the request genuinely fails.

Placing the signpost calls first and last, wrapping the entire method
body rather than just part of it, means the real interval shown in
Instruments' own timeline measures the true, full duration of
syncWithServer() - the real network request, the real JSON decode, and
the real assignment back to tasks - not just one piece of it. This
gives a real, precise, directly-measured answer to "how long does a
sync genuinely take, end to end" rather than an estimate pieced
together from separate Time Profiler samples.

ANSWER: Wrap syncWithServer()'s own body with
signposter.beginInterval("Sync With Server") at the start and a
deferred signposter.endInterval("Sync With Server", interval) call, so
the real interval shown in Instruments covers the method's true full
duration regardless of which code path it actually takes.

WHY THIS WORKS AS AN ANSWER
------------------------------
This correctly applies the chapter's own established beginInterval/
endInterval pattern to a real method from a prior chapter's capstone,
using defer to guarantee the interval closes on every real code path.