:: DeveloperApi ::
This class represent a unique identifier for a BlockManager.
The first 2 constructors of this class are made private to ensure that BlockManagerId objects
can be created only using the apply method in the companion object. This allows de-duplication
of ID objects. Also, constructor parameters are private to ensure that parameters cannot be
modified from outside this class.
:: DeveloperApi :: This class represent a unique identifier for a BlockManager.
The first 2 constructors of this class are made private to ensure that BlockManagerId objects can be created only using the apply method in the companion object. This allows de-duplication of ID objects. Also, constructor parameters are private to ensure that parameters cannot be modified from outside this class.