Function parallel_async

scrapy/utils/defer.py:280–295

Like ``parallel`` but for async iterators

(
    async_iterable: AsyncIterator[_T],
    count: int,
    callable: Callable[Concatenate[_T, _P], Deferred[Any] | None],  # noqa: A002
    *args: _P.args,
    **named: _P.kwargs,
)

def parallel_async(
    async_iterable: AsyncIterator[_T],
    count: int,
    callable: Callable[Concatenate[_T, _P], Deferred[Any] | None],  # noqa: A002
    *args: _P.args,
    **named: _P.kwargs,
) -> Deferred[list[tuple[bool, Iterator[Deferred[Any]]]]]:
    """Like ``parallel`` but for async iterators"""
    coop = Cooperator()
    work: Iterator[Deferred[Any]] = _AsyncCooperatorAdapter(
        async_iterable, callable, *args, **named
    )
    dl: Deferred[list[tuple[bool, Iterator[Deferred[Any]]]]] = DeferredList(
        [coop.coiterate(work) for _ in range(count)]
    )
    return dl


def process_chain(