(def default-streams-impl
{:make-reader (fn [x opts] (make-reader (make-input-stream x opts) opts))
:make-writer (fn [x opts] (make-writer (make-output-stream x opts) opts))
:make-input-stream (fn [x opts]
(throw (IllegalArgumentException.
(str "Cannot open <" (pr-str x) "> as an InputStream."))))
:make-output-stream (fn [x opts]
(throw (IllegalArgumentException.
(str "Cannot open <" (pr-str x) "> as an OutputStream."))))})