Turns Elixir data from the host, such as tool results, into the JSON-like values programs work with.

Atom keys and atoms become strings (except true, false and nil), tuples become lists, dates and times become ISO 8601 strings as JSON writes them, any other struct that implements String.Chars becomes its string (Decimal, as Jason would encode it), any other struct becomes a map, bytes that are not UTF-8 become U+FFFD, and values JSON cannot hold (pids, functions, references, ports) become nil.