Waiting for a Document to open

A common question I am asked is how to wait for a document to open (on a different thread to the one which called :Open) This is how I do that currently:

local thread = coroutine.running()

if not document:IsOpen() then
    document:OnceAfter("Open", function()
        task.defer(thread)
    end)
    coroutine.yield()
end

Warning: this implementation could yield indefinitely. You could use OnceFail to prevent this.