id property
id is used to uniquely identify multiple instances
of the same HydratedBloc type.
In most cases it is not necessary;
however, if you wish to intentionally have multiple instances
of the same HydratedBloc, then you must override id
and return a unique identifier for each HydratedBloc instance
in order to keep the caches independent of each other.
Implementation
@override
final String id;