* a size increase will be zeroed.
*
* Be careful to expand the buffer's size _before_ calling out external
* a size increase will be zeroed.
*
* Be careful to expand the buffer's size _before_ calling out external
* as necessary. The buffer's content is preserved. Setting a buffer's capacity
* is meant as a _hint_ to the underlying buffer and is only optimization; no
* guarantee is offered that subsequent calls to append or set_size will succeed.
* as necessary. The buffer's content is preserved. Setting a buffer's capacity
* is meant as a _hint_ to the underlying buffer and is only optimization; no
* guarantee is offered that subsequent calls to append or set_size will succeed.