> While it just so happens that all the ResponseWriters that net/http give you implement (e.g.) CloseNotifier, there’s not really any way for you to know that w

> While it just so happens that all the ResponseWriters that net/http give you implement (e.g.) CloseNotifier, there’s not really any way for you to know that without reading the source. Go editor tooling helps with this: gopls can do this nowadays (e.g. `lsp-find-implementation` in Emacs) and go oracle/guru may have already supported this back in 2014. It works both for finding implementations of an interface and finding interfaces implemented by a type.