-List)Create a lazy list representing the character codes in Stream.
List is a partial list ending in an attributed variable.
Unifying this variable reads the next block of data. The block is stored
with the attribute value such that there is no need to re-read it.
- Unlike the previous version of this predicate this version does not
require a repositionable stream. It does require a buffer size of at
least the maximum number of bytes of a multi-byte sequence (6).