extern void *buf_append(struct buffer_if *buf, int32_t amount);
extern void *buf_prepend(struct buffer_if *buf, int32_t amount);
extern void *buf_unappend(struct buffer_if *buf, int32_t amount);
extern void *buf_append(struct buffer_if *buf, int32_t amount);
extern void *buf_prepend(struct buffer_if *buf, int32_t amount);
extern void *buf_unappend(struct buffer_if *buf, int32_t amount);