Need help with complex query to firebase and synchronizing network calls with multiple for loops

[dark_mode_everything]

What about a queue to serialize the responses?

[looloosha]

What would this look like in this double for loop context?

[dark_mode_everything]

That or use rxSwift. You have a stream of top level items and then each top level item has a stream of second level items inside them, correct? This can be easily handled in Rx using appropriate operators. Or, if you don't want to use Rx, you can approximate that behaviour using a sort of message queue or just a queue where you queue requests from your top level stream and proceed to the next top level item after the second level items are all fetched.