code: protected static AbstractPlanNode addSendReceivePair(AbstractPlanNode scanNode) {
          SendPlanNode sendNode = new SendPlanNode();
          sendNode.addAndLinkChild(scanNode);
  
          ReceivePlanNode recvNode = new ReceivePlanNode();
          recvNode.addAndLinkChild(sendNode);
  
          return recvNode;
      }
docs: Insert a send receive pair above the supplied scanNode.
  @param scanNode that needs to be distributed
  @return return the newly created receive node (which is linked to the new sends)