问当我实际使用->meta时，我应该在什么时候让Moose类成为不可变的？

EN

BUILD {
  my $self = shift;
  use Module::Load;

  ### Use the arguments passed in to determine roles applicable to 
  ### this instance of the object. Load and apply roles.
  for my $role ($self->_determine_roles()) { 
    load $role;
    $role->meta->apply($self);
  }

  ### $self is now a Class::MOP::Class::__ANON__... anonymous class
  ### Should I then be saying I'm done mutating it with something like this?
  ### can make_immutable even be run on an object instance and not a package?
  $self->meta->make_immutable;
}