- command-line: _--anticache_ 
- mitmproxy shortcut: _o_, then _a_

When the __anticache__ option is passed to mitmproxy, it removes headers
(__if-none-match__ and __if-modified-since__) that might elicit a
304-not-modified response from the server. This is useful when you want to make
sure you capture an HTTP exchange in its totality, and during [client
replay](@!urlTo("clientreplay.html")!@).