libunftp v0.22.0

Changes in this release:

• #550 Split Authenticators from the Subject Resolving (UserDetail
  Providing) concern:
  • BREAKING: Refactored Authenticator trait to be non-generic and return Principal instead of a generic
    User
    type. This decouples authentication (verifying credentials) from user detail retrieval (obtaining full user
    information).
  • Introduced Principal struct representing an authenticated user's identity (username). This is the minimal
    information returned by authentication.
  • Introduced UserDetailProvider trait to convert a Principal into a full UserDetail implementation. This
    allows
    authentication and user detail lookup to be separated.
  • Introduced AuthenticationPipeline struct that combines an Authenticator and a UserDetailProvider to provide
    a
    complete authentication flow.
  • Added DefaultUserDetailProvider implementation that returns DefaultUser for convenience.
  • BREAKING: Updated all unftp-auth-* crates (unftp-auth-jsonfile, unftp-auth-pam, unftp-auth-rest) to
    use
    the new non-generic Authenticator trait.
  • Updated all examples and tests to use the new authentication pattern.
• #551 Let authenticators know the FTP Command channel TLS state
• #553 Introduced a new "pooled listener" mode
  (.pooled_listener_mode()) for high-traffic servers.
  • This mode improves passive connection performance and security by pre-binding all passive ports.
  • Fixed a memory leak in the passive port Switchboard (used by Pooled and Proxy modes). A new scavenger task now
    cleans up expired and orphaned port reservations.
  • Fixed the PORT command (Active Mode) so that it now works correctly in all listener modes.
  • Fixed that the EPSV command is now correctly disabled in Proxy Protocol mode where it is not (yet) supported.
• BREAKING: Removed the deprecated Server::new and Server::with_authenticator methods. The ServerBuilder
  struct should be used instead.