How to use the aioitertools.asyncio.ensure_future function in aioitertools

next_arg = 0

    while True:
        while next_arg < len(args) and (limit == -1 or len(pending) < limit):
            # We have to defer the creation of the Task as long as possible
            # because once we do, it starts executing, regardless of what we
            # have in the pending set.
            if args[next_arg] in input_map:
                input_map[args[next_arg]].append(next_arg)
            else:
                # We call ensure_future directly to ensure that we have a Task
                # because the return value of asyncio.wait will be an implicit
                # task otherwise, and we won't be able to know which input it
                # corresponds to.
                task: asyncio.Future[T] = asyncio.ensure_future(args[next_arg])
                pending.add(task)
                pos[task] = next_arg
                input_map[args[next_arg]] = [next_arg]
            next_arg += 1

        # pending might be empty if the last items of args were dupes;
        # asyncio.wait([]) will raise an exception.
        if pending:
            done, pending = await asyncio.wait(
                pending, loop=loop, return_when=asyncio.FIRST_COMPLETED
            )
            for x in done:
                if return_exceptions and x.exception():
                    ret[pos[x]] = x.exception()
                else:
                    ret[pos[x]] = x.result()