A middleware nobody had used since 2022

Five middleware on the command bus, of which two had a code path and three did not.

  transaction     used. moved to the two services
                  that needed it.
  authorisation   used once, on one command. moved to
                  the controller.
  logging         registered, and configured to log at
                  debug, into a channel discarding
                  debug. no output since 2022.
  retry           registered, and every command it
                  could retry is dispatched
                  synchronously from an HTTP request.
                  it has never retried anything.
  metrics         emitted a counter nobody had a
                  dashboard for.

Three of five doing nothing is the argument for removing the bus rather than for removing three middleware, because the machinery exists to support exactly this kind of composition and two concerns do not justify it. Each of the three had been registered once and never revisited, which is what a plugin architecture invites.