This interface is an internal implementation detail and will change without notice.
Clients that depend on
classes and interfaces can not expect to be compatible with any version
other than the version they were compiled against (even minor version and milestone releases may break binary
compatibility with respect to
Service that can decide whether a user can be deleted or not.
For example if a user is assigned to issues, then this account should not be deleted.
If a user delete is vetoed, then the system should disable the account instead, but remember the details of the old
account (display name and email address).