probelabs/goreplay ? reverse-engineered prompt

Build me a Go tool that can sit alongside a running web service, watch live HTTP traffic, and then replay that traffic into a staging or test environment so I can safely test deployments and config changes with real requests.

I want a simple command line app that can capture traffic from a port, show it to stdout for debugging, and send it to another HTTP endpoint for shadowing or load testing. It should also support reading from a file or other inputs, and writing to a few useful outputs like HTTP, file, TCP, Kafka, and maybe S3 if that fits. Make it easy to run in a container or from the terminal, with clear flags and sensible defaults.

If you need to check current docs or examples online while building it, go ahead. Please include basic tests and make sure the main workflow is easy to understand and use.