anchor.diff:  
   (defun write-all-mode! (path append binary data) :hidden
     (with (handle (open path (.. (if append "a" "w") (if binary "b" ""))))
  -    (if handle
  -      (progn
  -        (self handle :write data)
  -        (self handle :close)
  -        true)
  -      false)))
  +    (cond
  +      [handle
  +       (self handle :write data)
  +       (self handle :close)
  +       true]
  +      [else false])))
  +
  +(defun write-all-bytes-mode! (path append data) :hidden
  +  (with (handle (open path (if append "ab" "wb")))
  +    (cond
  +      [handle
  +       ;; Appending each byte at a time ends up being faster than generating
  +       ;; a string and appending it.
  +       (with (write (.> handle :write))
  +         (for-each byte data
  +           (write handle (string/char byte))))
  +       (self handle :close)
  +       true]
  +      [else false])))
   
   (defun write-all! (path data)
     "Writes the string DATA to the file at PATH.
  
positive.code:    > (write-bytes! \"tests/data/abc_.txt\" `(97 98 99))
     out = true
     ```"
    (write-all-mode! path false true (string/bytes->string data)))
  
  (defun append-all! (path data)
    "Appends the string DATA to the file at PATH.
  
negative.code:    > (append-bytes! \"tests/data/abc_.txt\" `(100 101 102))
     out = true
     ```"
    (write-all-bytes-mode! path true data))
  