anchor.diff:  
           (:be
            ;; Zero out the :be stable bits we just took out.
  -         (setf (ldb byte-specification (bit-stable bitio))
  +         (setf (ldb byte-specification (read-bit-stable bitio))
                  0)
            ;; remove the accounting of the bits from the stable.
            (decf (num-bits-in-stable bitio) num-selected-bits)
  
positive.code:       ;; Oops, had an EOF
        ((equal result eof-value)
         (setf (num-bits-in-stable bitio) 0
               (bit-stable bitio) 0)
         NIL)
        ;; all good.
        (t
         (setf (num-bits-in-stable bitio) 8
               (bit-stable bitio) result)
         T))))
  
  ;; This is not entirely a fast-path since it doesn't read a sequence.
  (defun fast-path/octet-aligned-bit-read (bitio bit-read-count bit-endian
                                           &optional (eof-error-p T)
                                             (eof-value NIL))
    "This function assumes the bit-stable is empty in the BITIO stream
  and BIT-READ-COUNT is a multiple of 8.  It reads BIT-READ-COUNT bits
  from the BITIO stream (reading the actual bits in each octet in
  BIT-ENDIAN manner) and then places them into an integer that it returns.
  
negative.code:     ;; Note: we can only consume up to the amount in the stable, so
      ;; if there is an EOF we cannot detect it here yet.
      (multiple-value-bind (prefix-stable-bits num-prefix-stable-bits-read)
          (consume-read-bit-stable bitio bits-remaining-to-read bit-endian)
  
        (decf bits-remaining-to-read num-prefix-stable-bits-read)
  
  