SPA_FEATURE_ALLOCATION_CLASSES
if (!spa_feature_is_enabled(spa, SPA_FEATURE_ALLOCATION_CLASSES)) {
zfeature_register(SPA_FEATURE_ALLOCATION_CLASSES,
ASSERT(spa_feature_is_enabled(spa, SPA_FEATURE_ALLOCATION_CLASSES));
spa_feature_incr(spa, SPA_FEATURE_ALLOCATION_CLASSES, tx);
SPA_FEATURE_ALLOCATION_CLASSES)) {