NPAL14110 : When we get an output value at the end of execution of a node
and if that value is an output of a SubGraph corresponding to a MacroNode,
that value was transmitted immediatly. So a node of the Graph of that
MacroNode may be activated before the End of execution of the SubGraph. And
moreover, if there was a loop in the SubGraph, that output value was
transmitted for each step of the loop. So a same node in the Graph of the
MacroNode may be activated a few times for each output value.
Now output values of a subgraph are transmitted to the corresponding
MacroNode only once at the end of the SubGraph (CheckAllDone method)
