Create a lazy list representing the character codes (chars) 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).