Add an option to easily regenerate http-data files (#5040)
Add an option to easily regenerate http-data files (#5040)

* Add `RECORD=force` to regenerate existing files
* Add `RECORD=passthrough` to preserve the old behavior. There may not
  be a use-case for this, alternatively we could drop this entirely.

When not in the legacy passthrough mode, a status 200 response with no
headers and an empty body is generated.

Co-authored-by: Justin Geibel <48bcd14f59eb40d23faea74ffe3fc874e7cc46a2@gmail.com>
rust-lang/crates.io,rust-lang/crates.io,rust-lang/crates.io,rust-lang/crates.io