Thanks, filed as FB21232935 edit: This duplicate comment brought to you by a UI error indicating the prior message could not be sent, and I should 'try again in a few minutes'.

Thanks, filed as FB21232935

Thanks, filed FB21232935 for this.

Thanks Aaron, that's very informative. I was wondering if you could speak to some of the workloop-specific differences if possible. Why is dispatch_sync unsupported on workloops? And in the 'multiple serial queues targeting a single workloop' case, why is it noted that dispatch_sync is discouraged for 'performance reasons'? Do those same performance concerns not apply in other configurations where serial queues ultimately target another serial queue?