ESC_NF_SDTR_SENT
nexus->flags |= ESC_NF_SDTR_SENT;
if (nexus->flags & ESC_NF_SDTR_SENT) {
nexus->flags &= ~ESC_NF_SDTR_SENT;
if (!(nexus->flags& ESC_NF_SDTR_SENT))
nexus->flags &= ~ESC_NF_SDTR_SENT;