This module implements string buffers that automatically expand
as necessary. It provides accumulative concatenation of strings
in quasi-linear time (instead of quadratic time when strings are
create n returns a fresh buffer, initially empty.
The n parameter is the initial size of the internal string
that holds the buffer contents. That string is automatically
reallocated when more than n characters are stored in the buffer,
but shrinks back to n characters when reset is called.
For best performance, n should be of the same order of magnitude
as the number of characters that are expected to be stored in
the buffer (for instance, 80 for a buffer that holds one output
line). Nothing bad will happen if the buffer grows beyond that
limit, however. In doubt, take n = 16 for instance.
If n is not between 1 and Sys.max_string_length, it will
be clipped to that interval.
Empty the buffer and deallocate the internal string holding the
buffer contents, replacing it with the initial internal string
of length n that was allocated by Buffer.createn.
For long-lived buffers that may have grown a lot, reset allows
faster reclaimation of the space used by the buffer.