I second this type of approach - when I developed an iOS app that needed to display the results of multiple long-running API requests made on the server-side, I

I second this type of approach - when I developed an iOS app that needed to display the results of multiple long-running API requests made on the server-side, I had the app make a request and then wait for data to be pushed to the device on a persistent "back-channel" connection the app kept open. This way data could be displayed as it was available, but the app didn't need to poll or open multiple TCP connections (expensive on EDGE, which was common at the time).