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).

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

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.

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

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.

Rehydrate the sequencer EphemeralState from the backing persisted store

If timestamp provided, it will compute the state up until (inclusive) that timestamp. If none provided, it will compute the state at current head.

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.

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. Must be equal or greater than any prior set lower bound.

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