I'm not seeing how this is pull in any sense. Calling recv on the channel doesn't cause any result to be computed. The push of the previous operators will cause the compution to continue.

EDIT: Ok, I guess because they are bounded to 1, the spcs will let the pushing computation continue first after the "puller" has read the result, but it's more like pushing with back-pressure.

It is pull in the sense that an operator can call `recv().await` (the equivalent of `input.next()` in the article) at any point, which can then block the execution of the operator until more data is available.

It is push in the sense that an operator can call `send(x).await` (the equivalent of `out(x)` in the article) at any point, which can then block the execution of the operator until the data is consumed.

So it is a hybrid of both pull and push. You can, at any point, block on either pulling data or pushing data.