UNSTABLE: New API, yet to be vetted.

An operation on a Deno.Kv that can be performed atomically. Atomic operations do not auto-commit, and must be committed explicitly by calling the commit method.

Atomic operations can be used to perform multiple mutations on the KV store in a single atomic transaction. They can also be used to perform conditional mutations by specifying one or more Deno.AtomicChecks that ensure that a mutation is only performed if the key-value pair in the KV has a specific versionstamp. If any of the checks fail, the entire operation will fail and no mutations will be made.

The ordering of mutations is guaranteed to be the same as the ordering of the mutations specified in the operation. Checks are performed before any mutations are performed. The ordering of checks is unobservable.

Atomic operations can be used to implement optimistic locking, where a mutation is only performed if the key-value pair in the KV store has not been modified since the last read. This can be done by specifying a check that ensures that the versionstamp of the key-value pair matches the versionstamp that was read. If the check fails, the mutation will not be performed and the operation will fail. One can then retry the read-modify- write operation in a loop until it succeeds.

The commit method of an atomic operation returns a value indicating whether checks passed and mutations were performed. If the operation failed because of a failed check, the return value will be null. If the operation failed for any other reason (storage error, invalid value, etc.), an exception will be thrown. If the operation succeeded, the return value will be a Deno.KvCommitResult object containing the versionstamp of the value committed to KV.