CEPH_OPT_TCP_NODELAY
#define CEPH_OPT_DEFAULT (CEPH_OPT_TCP_NODELAY)
opt->flags |= CEPH_OPT_TCP_NODELAY;
opt->flags &= ~CEPH_OPT_TCP_NODELAY;
if ((opt->flags & CEPH_OPT_TCP_NODELAY) == 0)