working on new ID based join iterator

Author: hmottestad

core/sail/lmdb/src/main/java/org/eclipse/rdf4j/sail/lmdb/LmdbDupRecordIterator.java

@@ -28,6 +28,7 @@
 import java.nio.ByteOrder;
 
 import org.eclipse.rdf4j.common.concurrent.locks.StampedLongAdderLockManager;
+import org.eclipse.rdf4j.query.algebra.Var;
 import org.eclipse.rdf4j.sail.SailException;
 import org.eclipse.rdf4j.sail.lmdb.TripleStore.DupIndex;
 import org.eclipse.rdf4j.sail.lmdb.TxnManager.Txn;