Swift: Outbox depth

outboxDepth() counts the queued mutations that no run has settled. It is the number a screen shows as pending work, and it reaches zero once every write has an applied or rejected verdict.

Examples#

Basic#

// TodoApp/TodoListView.swift (excerpt)
import KizunaSync

let pending = try await kizunasync.outboxDepth()

Keep a badge in sync#

// TodoApp/TodoListView.swift (excerpt)
import KizunaSync

let stop = try await kizunasync.on { event in
  if case .queueDepth(let depth) = event {
    Task { @MainActor in badge = Int(depth) }
  }
}

Parameters#

Returns#

Int, the number of outbox entries that are not in flight. A write that a push is carrying right now is not counted, so the number drops as verdicts arrive rather than after the whole run finishes.

Errors#

Notes#

Every successful write raises QUEUE_DEPTH with the same number, so a view can follow the count through Subscribe to events instead of polling this method. A depth that never falls means the runs are failing; the reason is in the last error a run threw, and a write the retry budget finally dropped appears in List rejections with kind DEAD_LETTER.

The count says nothing about attachment bytes. An upload that is queued after the outbox drains is tracked by Get attachment status.

Related reference#

• Sync
• Subscribe to events
• List rejections
• Kotlin: Outbox depth
• JavaScript: Outbox depth