(let ((stream (flexi-streams:make-in-memory-input-stream
	       (map 'vector #'char-code '(#\f #\o #\o #\b #\a #\r #\newline)))))
  (with-open-file (out "foo" :direction :output
		       :element-type '(unsigned-byte 8))
    (loop :with byte
       :while (setf byte (read-byte stream nil))
       :do (write-byte byte out))))