protected void copyFromNext(SeekerState nextState) {
      keyBuffer = nextState.keyBuffer;
      currentKey.setKey(nextState.keyBuffer,
        nextState.currentKey.getRowPosition() - Bytes.SIZEOF_SHORT, nextState.keyLength);

      startOffset = nextState.startOffset;
      keyOffset = nextState.keyOffset;
      valueOffset = nextState.valueOffset;
      keyLength = nextState.keyLength;
      valueLength = nextState.valueLength;
      nextKvOffset = nextState.nextKvOffset;
      memstoreTS = nextState.memstoreTS;
      currentBuffer = nextState.currentBuffer;
      tagsLength = nextState.tagsLength;
    }
Copy the state from the next one into this instance (the previous state placeholder). Used to
save the previous state when we are advancing the seeker to the next key/value.
hbase-common/src/main/java/org/apache/hadoop/hbase/io/encoding/RowIndexSeekerV1.java