Many times I need to test my web interfaces, for example, when an I need to make a placeholder loading effect, but the server response too fast so is impossible to see what I'm working.

Fortunately, Google Chrome offer the Network Profiles, I don't like to use the default profiles available because I think is too slow, so in these days ago I found one profile well to work and the result was something like this:

That's it! Of course you can adapt for your necessaries.