CHAN_RBUF
sshbuf_check_reserve(c->input, CHAN_RBUF) == 0)
sshbuf_check_reserve(c->input, CHAN_RBUF) == 0)
char buf[CHAN_RBUF];
char buf[CHAN_RBUF];
char buf[CHAN_RBUF];
len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF));
char rbuf[CHAN_RBUF];