@Override
  public void beforeIterJoinOfSingleIndexResults(Index usedIndex, Index unusedIndex) {}
Asif :Invoked before intermediate resultset is iter evaluated to be used with the usable index
of the operand for filter evaluatable Composite CompiledComparison for an AND type
CompositeGroupJunction containing more than one filter evaluatable composite condition. This
invocation implies that the indpendent group of iterators of one of the operands of the
condition is also present in the intermediate resultset which means that index for that operand
canot be used. Thus the intermediate Resultset is iterated & for each tuple , the values set in
the respective RuntimeIterators. The operand without usable index is evaluated & the Index on
the other operand is used to get resultset for that value. Thus for each tuple we query the
index on other operand .

@param usedIndex : The Index which will be used to obtain the ResultSet
@param unusedIndex : The Index which does not get used as the relevant iterators are present in
       the intermediate resultset
geode-core/src/main/java/org/apache/geode/cache/query/internal/QueryObserverAdapter.java