@Override
  public DistributionMessage createRequestMessage(Set<InternalDistributedMember> singleton,
      FunctionStreamingResultCollector processor, boolean isReExecute,
      boolean isFnSerializationReqd) {
    return null;
  }
ResultReceiver (which could be resultCollector?)will be instantiated and will be used to send
messages and receive results from other nodes. It takes a set of nodes to which functionExecution
message has to be sent. Creates one message for each and sends it to each of them. Then it gets
result in processData where it adds them to the resultCollector.
geode-core/src/main/java/org/apache/geode/internal/cache/execute/PartitionedRegionFunctionResultWaiter.java