This method compares the receiving object to the object supplied in the
other argument.
This is a default implementation which compares two items based on their
identityHash.
This method returns -1 if the
other is larger than the receiving object,
0 if the two objects are equal, and
1 if other is smaller
than the receiving object.
Note
Classes inheriting from Orderable
(like builtin classes
File,
DateTime, or
TimeSpan)
are strongly encouraged to forward to this default implementation for
comparison cases not covered by their class-specific
compareTo implementation.
