bwillwrite
bwillwrite(chunk);
void bwillwrite(int bytes);
bwillwrite(uio->uio_resid);
bwillwrite(FUSE_BLKSIZE);
bwillwrite(HAMMER_XBUFSIZE);
bwillwrite(blksize);
bwillwrite(HAMMER2_PBUFSIZE);
bwillwrite(node->tn_blksize);
bwillwrite(HAMMER2_PBUFSIZE);