The scheduler had a 'nice' optimization where any newly
submitted or resumed task would try and check if the current
thread its executing was the process event thread and if so
directly start or resume the task rather than pushing it into
the FIFO queues. Well this has a bad side effect of a recursive
task which generates sub tasks will eventually cause a
stackoverflow to occur. To avoid this the tasks for
submitting and resuming go through the normal FIFO queue which
is slower but removes the recursive function calls.
Turns out that the final_suspend() method is required
to be std::suspend_always() otherwise the coroutine_handle<>.done()
function will not trigger properly. Refactored the task class
to allow the user to decide if they want to suspend at the beginning
but it now forces a suspend at the end to guarantee that
task.is_ready() will work properly.
