Expose message fields

[austinabell]

Summary of changes
Changes introduced in this pull request:

• The only reason to have kept from being public was for if the Cid was to be cached later, but doesn't really seem like much of a reason to keep. I didn't remove the pattern altogether for backwards compatibility and for convenience in certain places (just testing things)
  • Avoids runtime checks for these commonly used funcs so kinda a micro optimization lol

Main reason is just because rust-analyzer is borked and gives errors on builder patterns

Reference issue to close (if applicable)

Closes

Other information and links

[ec2]

I think the folks at Zondax use our Message library. Should probably tag them here. Not sure who to tag though.

[austinabell]

I think the folks at Zondax use our Message library. Should probably tag them here. Not sure who to tag though.

It's not a breaking change but @jleni. I will bump the patch version and release this