anchor.diff:  <% if entity.extends -%>
       super.performLink();
   <% else -%>
  -    org.realityforge.braincheck.Guards.invariant( () -> _$linking,
  -                                                  () -> "performLink invoked from outside link" );
  +    if ( org.realityforge.braincheck.BrainCheckConfig.checkInvariants() )
  +    {
  +      org.realityforge.braincheck.Guards.invariant( () -> _$linking,
  +                                                    () -> "performLink invoked from outside link" );
  +    }
   <% end -%>
   <% linkable_attributes.select{|attribute| attribute.arez.eager? }.each do |attribute| -%>
       link<%= attribute.arez.name %>();
  
positive.code:     if( null == _<%= Reality::Naming.camelize(attribute.arez.name) %> <%= attribute.nullable? ? "&& null != _#{Reality::Naming.camelize(attribute.referencing_link_name)}" :'' %> )
      {
        _<%= Reality::Naming.camelize(attribute.arez.name) %> = _entityLocator.findByID( <%= (attribute.remote_reference? ? attribute.referenced_remote_entity : attribute.referenced_entity).arez.qualified_name %>.class, _<%= Reality::Naming.camelize(attribute.referencing_link_name) %> );
        org.realityforge.braincheck.Guards.invariant( () -> null != _<%= Reality::Naming.camelize(attribute.arez.name) %>,
                                                      () -> "Unable to locate entity of type '<%= (attribute.remote_reference? ? attribute.referenced_remote_entity : attribute.referenced_entity).arez.qualified_name %>' and id = '" + _<%= Reality::Naming.camelize(attribute.referencing_link_name) %> + "' via '<%= attribute.arez.name %>' attribute on " + this );
  <% if !attribute.remote_reference? && attribute.inverse.arez.traversable? && attribute.inverse.multiplicity == :many %>        _<%= Reality::Naming.camelize(attribute.arez.name) %>.add<%= attribute.inverse.name %>( this );<% end -%>
  <% if !attribute.remote_reference? && attribute.inverse.arez.traversable? && attribute.inverse.multiplicity != :many %>        _<%= Reality::Naming.camelize(attribute.arez.name) %>.linkSet<%= attribute.inverse.name %>( this );<% end -%>
  
  
negative.code: <% if entity.extends -%>
      super.performDelink();
  <% else -%>
      if ( org.realityforge.braincheck.BrainCheckConfig.checkInvariants() )
      {
        org.realityforge.braincheck.Guards.invariant( () -> _$delinking,
                                                      () -> "performDelink invoked from outside delink" );
      }
  <% end -%>
  <% linkable_attributes.each do |attribute| -%>
      delink<%= attribute.arez.name %>();
  