Printing out everything managed by a custodian

dump-custodian.rkt

(on (message (dump-debug-info))
    (local-require racket/exn)
    (local-require racket/tcp)
    (printf "------------------------------------------------------------\n")
    (for [(index (in-naturals))
          (item (custodian-managed-list (current-custodian) outer-custodian))]
      (printf "\nItem ~a.\n~v\n" index item)
      (cond
        [(thread? item)
         (printf "Thread: (dead? ~v)\n~a"
                 (thread-dead? item)
                 (exn->string (exn "Stack snapshot:" (continuation-marks item))))]
        [(tcp-port? item)
         (printf "TCP port: (addresses ~v)\n"
                 (call-with-values (lambda () (tcp-addresses item #t)) list))]
        [else (void)])))