What is the $stateRegistryProvider service in angularjs's routing library angular-ui/ui-router?

I can understand the function and usage of $stateProvider in

angular-ui/ui-router, but what is $stateRegistryProvider for?
ask the boss for advice. It would be nice to have an example.

Jan.27,2022
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3164e-2b0f3.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3164e-2b0f3.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?