Class responsible for converting between an object and its id.

This, the default implementation, uses an object's local ObjectSpace __id__ as its id. This means that an object's identification over drb remains valid only while that object instance remains alive within the server runtime.

For alternative mechanisms, see DRb::TimerIdConv in rdb/timeridconv.rb and DRbNameIdConv in sample/name.rb in the full drb distribution.