hollow/src/main/java/com/netflix/hollow/api/producer/ReadStateHelper.java
ReadStateHelper swap() {
        return new ReadStateHelper(newReadState(current.getVersion(), pending.getStateEngine()),
                newReadState(pending.getVersion(), current.getStateEngine()));
    }
ReadStateHelper swap() {
        return new ReadStateHelper(newReadState(current.getVersion(), pending.getStateEngine()),
                newReadState(pending.getVersion(), current.getStateEngine()));
    }
ReadStateHelper swap ( ) { return new ReadStateHelper ( newReadState ( current . getVersion ( ) , pending . getStateEngine ( ) ) , newReadState ( pending . getVersion ( ) , current . getStateEngine ( ) ) ) ; }
Swap underlying state engines between current and pending while keeping the versions consistent;
used after delta integrity checks have altered the underlying state engines.

@return
Swap underlying state engines between current and pending while keeping the versions consistent ; used after delta integrity checks have altered the underlying state engines .