public boolean removeAndStopRegionEngine(final long regionId) {
        final RegionEngine engine = this.regionEngineTable.get(regionId);
        if (engine != null) {
            engine.shutdown();
            return true;
        }
        return false;
    }
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