SyncActor.swift

actor SyncActor {

    var syncRequests = 0

    private func sync() async {
        // Make sure only one sync is in progress at the same time
        // (because of actor re-entrancy another sync could be started while we await for the persistence/network operations)
        self.syncRequests += 1
        if self.syncRequests > 1 {
            // Sync already in progress
            return
        }
        
        // ... sync operation with awaiting persistence / networking logic here ...
        
        self.syncRequests -= 1
        if self.syncRequests > 0 {
            self.syncRequests = 0
            // If another sync was requested during syncing, trigger another sync operation
            Task.detached {
                await self.sync()
            }
        }
    }
    
}