sbuf_new_for_sysctl
sb = sbuf_new_for_sysctl(NULL, NULL, 4096, req);
sbuf_new_for_sysctl(&sb, NULL, 256, req);
sbuf_new_for_sysctl(&sb, NULL, 512, req);
sbuf_new_for_sysctl(&sb, NULL, 8, req);
sbuf_new_for_sysctl(&sb, NULL, 8, req);
struct sbuf *sbuf_new_for_sysctl(struct sbuf *, char *, int,