MAX_CHUNK
if (count > MAX_CHUNK) {
for (pos = MAX_CHUNK; pos < count; pos += MAX_CHUNK) {
sz = MINIMUM(MAX_CHUNK,
blk.len = MAX_CHUNK; /* Doesn't matter. */
sz = MAX_CHUNK < (u->bufsz - u->bufpos) ?
MAX_CHUNK : (u->bufsz - u->bufpos);