What is Difference between ROLLBACK IMMEDIATE and WITH NO_WAIT during ALTER DATABASE?

ROLLBACK AFTER integer [SECONDS] | ROLLBACK IMMEDIATE:

Specifies whether to roll back after a specified number of seconds or immediately if transaction is not complete.
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NO_WAIT:

Specifies that if the requested database state or option change cannot complete immediately without waiting for transactions to commit or roll back on their own, then the request will fail.

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