Shopify/toxiproxy — reverse-engineered prompt

Build me a developer tool called Toxiproxy that lets people test how their apps behave when network connections get slow, broken, flaky, or unavailable.

It should run as a TCP proxy service. Users should point their app’s test connections through it, then control those connections through an HTTP API and a command line tool. They need to be able to create proxy mappings like local port to real Redis or MySQL, list them, enable or disable them, and add network problems such as latency, timeout, bandwidth limits, slow close, connection reset, sliced data, and limited data.

Please make it useful for local development and CI, not a fancy UI. Include a Go client library, tests, Docker support, clear install and usage docs, and examples showing how someone could simulate Redis going down or MySQL becoming slow during a test. Also include basic metrics so users can see proxy activity. Look up current Go docs if you need to.