hollow/src/main/java/com/netflix/hollow/core/util/StateEngineRoundTripper.java
public static void roundTripSnapshot(HollowWriteStateEngine writeEngine, HollowReadStateEngine readEngine) throws IOException {
        roundTripSnapshot(writeEngine, readEngine, null);
    }
public static void roundTripSnapshot(HollowWriteStateEngine writeEngine, HollowReadStateEngine readEngine) throws IOException {
        roundTripSnapshot(writeEngine, readEngine, null);
    }
Populate the provided {@link HollowReadStateEngine} with the dataset currently in the provided {@link HollowWriteStateEngine}

@param writeEngine the write state engine
@param readEngine the read state engine
@throws IOException if the round trip from write to read state failed