Do tornado AsyncHTTPClient fetch callbacks get called in order of request or response?

Question

I'm using Tornado's AsyncHTTPClient to fetch a URL multiple times. I pass in a different callback with each request.

If I send requests A, B (with associated callbacks Callback_A and Callback_B) to a URL, but the responses come back in the opposite order B, A. Should I expect the callbacks to be called in the order of Callback_A, Callback_B or will they get called in the opposite order?

I'd like to have the callbacks called in the order of responses (so Callback_B, Callback_A). If that's not the default behavior is there a way to do that instead?

Answer 1

Callbacks are executed as soon as possible after the event for which they're waiting is complete. So, they are called in response order.