Construct already completed task

What’s the best way to construct a Task which has already completed? My current best shot is

t = @async nothing

but this feels both clumsy and inefficient.

The use case is that I would like to have a background task with the following behaviour.

  • Start when work comes in and there isn’t already a background task running.
  • Keep running while there’s work, then shut down once there’s no more work left.

In somewhat pseudo-code-ish Julia, this can be achieved as follows.

# Initialize
work_queue = []
t = task_which_is_already_done()

# When work comes in
push!(work_queue, work)
if istaskdone(t)
    t = @async begin
        while !isempty(work_queue)