Enqueue a task execution.  It will run in the background as soon
        as the coordinator clears it to do so.

def enqueue_task(self, source, *args):
        """ Enqueue a task execution.  It will run in the background as soon
        as the coordinator clears it to do so. """
        yield from self.cell.coord.enqueue(self)
        route = Route(source, self.cell, self.spec, self.emit)
        self.cell.loop.create_task(self.coord_wrap(route, *args))
        # To guarantee that the event loop works fluidly, we manually yield
        # once. The coordinator enqueue coroutine is not required to yield so
        # this ensures we avoid various forms of event starvation regardless.
        yield