All header transformation code from h2mux has been consolidated in the connection package since it's used by both h2mux and http2 logic.
Exported headers used by proxying between edge and cloudflared so then can be shared by tunnel service on the edge.
Moved access-related headers to corresponding packages that have the code that sets/uses these headers.
Removed tunnel hostname tracking from h2mux since it wasn't used by anything. We will continue to set the tunnel hostname header from the edge for backward compatibilty, but it's no longer used by cloudflared.
Move bastion-related logic into carrier package, untangled dependencies between carrier, origin, and websocket packages.
- Move packages the provide generic functionality (such as config) from `cmd` subtree to top level.
- Remove all dependencies on `cmd` subtree from top level packages.
- Consolidate all code dealing with token generation and transfer to a single cohesive package.
We removed all token validation from cloudflared and now rely on
the edge to do the validation. This is better because the edge is
the only thing that fully knows about token revocation. So if a user
logs out or the application revokes all it's tokens cloudflared will
now handle that process instead of barfing on it.
When we go to fetch a token we will check for the existence of a
lock file. If the lock file exists, we stop and poll every half
second to see if the lock is still there. Once the lock file is
removed, it will restart the function to (hopefully) go pick up
the valid token that was just created.
