You can simulate bad wifi with the throttling option on the network tab of your browser's developer tools

Oh? How does that help for native applications?

You can always also simulate bad WiFi by walking away from your access point until you have bad wifi

That's unfortunately very inconvenient when you work on an embeddeded device prototype that consists of several boards interconnected by hair thin wires :)

Maybe I should make some friends across the street to the point they give me access to their APs...