@Override
    public String toString() {
        return "StoreEngine{storeId=" + storeId + ", startTime=" + startTime + ", dbPath=" + dbPath + ", storeOpts="
               + storeOpts + ", started=" + started + ", regions=" + getAllRegionEngines() + '}';
    }
Storage engine, there is only one instance in a node,
containing one or more {@link RegionEngine}.

@author jiachun.fjc
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/StoreEngine.java