WRITE-SEQUENCE() should update index for OCTET-OUTPUT-STREAMs.
WRITE-SEQUENCE() should update index for OCTET-OUTPUT-STREAMs.

Test case:

(let ((stream (make-octet-output-stream)))
  (macrolet ((%sov (&rest values)
               `(map 'simple-octet-vector #'identity #(,@values))))
    (write-sequence #(1 2 3 4 5) stream)
    (write-sequence (%sov 6 7 8 9 10) stream)
    (write-sequence (%sov 11 12 13 14 15) stream :start 1 :end 3)
    (write-sequence (%sov 16 17 18 19 20) stream :end 3)
    (write-sequence (%sov 21 22 23 24 25) stream :start 3)
    (values (index stream)
            (get-output-stream-octets stream)
            (get-output-stream-octets stream))))

EXPECTED: (values 17 #(1 2 3 4 5 6 7 8 9 10 12 13 16 17 18 24 25) #())
ACTUAL: (values 5 #(1 2 3 4 5) #())

eadmund/ironclad,sharplispers/ironclad,froydnj/ironclad,glv2/ironclad