public void __enter__()
{
if (_new_stack)
{
// Clear the control_dependencies graph.
_old_stack = _graph._control_dependencies_stack;
_graph._control_dependencies_stack = new Queue <_ControlDependenciesController>();
// Clear the control_flow_context too.
_old_control_flow_context = _graph._get_control_flow_context();
_graph._set_control_flow_context(null);
}
_graph._push_control_dependencies_controller(this);
}