The core of DeferOperation

core of deferoperation

  // must take the deferral early while the event is still on the stack. 
  auto op = make_operation_pattern(sop(t));
  typedef decltype(op) OP;

  return Using(
      // resource factory
      [=]()
      {
          return op;
      },
      // observable factory
      [sob, t](OP op)
      {
          return sob(op, t);
      });