@Override
    public void describe(final Printer out) {
        out.println("StoreEngine:"); //
        out.print("  AllLeaderRegions:") //
            .println(getLeaderRegionIds()); //
        for (final RegionEngine r : getAllRegionEngines()) {
            r.describe(out);
        }
    }
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