Write an acknowledgement that member has processed earlier timestamps. Only the latest timestamp needs to be stored. Earlier timestamps can be overwritten. Acknowledgements of earlier timestamps should be ignored.

Add a new events to the sequencer store. Callers must ensure that all members receiving a counter update have been registered and that the counter values are correct. Callers must also ensure that the timestamp is correct and later than all prior events as this is also not validated by all store implementations. Counter updates for invalid counter values (<0) will cause a java.lang.IllegalArgumentException to be throw. Implementations may throw a java.lang.IllegalArgumentException if a counter update is incorrect (not following the current head), but may not if this is not possible to efficiently do (like with database persistence that would require executing a query to check). Implementations should ensure that all events are written atomically (or none written if a failure is hit).

Updates the in-flight aggregations for the given aggregation IDs. Only adds or updates aggregations, but never removes them.

Adds a new member to the sequencer. Callers are expected to ensure that the member is not already registered.

Removes a shutdown task from the list using a token returned by runOnShutdown

Blocks until all earlier tasks have completed and then prevents further tasks from being run.

Prevents member from sending and reading from the sequencer, and allows unread data for this member to be pruned. It however won't stop any sends addressed to this member.

Fetch the lower bound of events that can be read. Returns None if all events can be read.

Retrieve the timestamp of the initial topology snapshot if available.

Check whether we're closing. Susceptible to race conditions; unless you're using using this as a flag to the retry lib or you really know what you're doing, prefer performUnlessClosing and friends.

Check whether the member is enabled. Currently used when receiving a request for reading.

track running futures on shutdown

set to true to get detailed information about all futures that did not complete during shutdown. if set to false, we don't do anything.

Return the latest acknowledgements for all members

How often to poll to check that all tasks have completed.

Use this method to create a PromiseUnlessShutdown that will automatically be cancelled when the close context is closed. This allows proper clean up of stray promises when the node is transitioning to a passive state.

Note: you should *not* invoke success on the returned promise but rather use trySuccess. The reason is that the call to success may fail in case of shutdown.

Blocks until all earlier tasks have completed and then prevents further tasks from being run.

Performs the task given by f unless a shutdown has been initiated. The shutdown will only begin after f completes, but other tasks may execute concurrently with f, if started using this function, or one of the other variants (performUnlessClosingF and performUnlessClosingEitherT). The tasks are assumed to take less than closingTimeout to complete.

DO NOT CALL this.close as part of f, because it will result in a deadlock.

Performs the EitherT[Future] given by etf unless a shutdown has been initiated, in which case the provided error is returned instead. Both etf and the error are lazy; etf is only evaluated if there is no shutdown, the error only if we're shutting down. The shutdown will only begin after etf completes, but other tasks may execute concurrently with etf, if started using this function, or one of the other variants (performUnlessClosing and performUnlessClosingF). The tasks are assumed to take less than closingTimeout to complete.

DO NOT CALL this.close as part of etf, because it will result in a deadlock.

Performs the Future given by f unless a shutdown has been initiated. The future is lazy and not evaluated during shutdown. The shutdown will only begin after f completes, but other tasks may execute concurrently with f, if started using this function, or one of the other variants (performUnlessClosing and performUnlessClosingEitherT). The tasks are assumed to take less than closingTimeout to complete.

DO NOT CALL this.close as part of f, because it will result in a deadlock.

Removes all in-flight aggregations that have expired before or at the given timestamp

Rehydrate the sequencer EphemeralState from the backing persisted store

Extract a range of events for a member. It is expected that the sequencer will validate requests against its current state so read requests for unregistered members or counter ranges that do not exist should just return an empty source.

Same as runOnShutdown_ but returns a token that allows you to remove the task explicitly from being run using cancelShutdownTask

Register a task to run when shutdown is initiated.

You can use this for example to register tasks that cancel long-running computations, whose termination you can then wait for in "closeAsync".

Save an updated lower bound of events that can be read along with the optional timestamp of the initial onboarding topology snapshot.

The lower bound of events ts must be equal or greater than any prior set lower bound. The value of maybeOnboardingTopologyTimestamp is only set if nonEmpty and only on the initial call.

Build a status object representing the current state of the sequencer.