While tie in perldoc allows tying to an arbitrary object, the class in question
must support this in its implementation of TIEHASH, TIEARRAY or
This class provides a very tie constructor that simply returns the object it
was given as its first argument.
This way side effects of calling $object->TIEHASH are avoided.
This is used in Data::Visitor in order to tie a variable to an already
existing object. This is also useful for cloning, when you want to clone the
internal state object instead of going through the tie interface for that