@Override
          public boolean advance() {
            // We have one Cell only so return true first time then false ever after.
            if (!hasCell) {
              return hasCell;
            }

            hasCell = false;
            return true;
          }
@param index the index of the cell to use as its value
@return A faked out 'Cell' that does nothing but return index as its value
hbase-client/src/test/java/org/apache/hadoop/hbase/ipc/TestHBaseRpcControllerImpl.java