The approximate timestamp

This is either the last observed sequencer timestamp OR the effective timestamp after we observed the time difference of (effective - sequencer = epsilon) to elapse

Wait for a condition to become true according to the current snapshot approximation

Waits until a snapshot is available

Supervised version of awaitSnapshot

Shutdown safe version of await snapshot

Supervised version of awaitSnapshotUS

Returns an optional future which will complete when the timestamp has been observed

If the timestamp is already observed, we return None.

Note that this function allows to wait for effective time (true) and sequenced time (false). If we wait for effective time, we wait until the topology snapshot for that given point in time is known. As we future date topology transactions (to avoid bottlenecks), this might be before we actually observed a sequencing timestamp.

Overloaded recent snapshot returning derived type

The domain this client applies to

Possibly future dated head snapshot

As we future date topology transactions, the head snapshot is our latest knowledge of the topology state, but as it can be still future dated, we need to be careful when actually using it: the state might not yet be active, as the topology transactions are future dated. Therefore, do not act towards the sequencer using this snapshot, but use the currentSnapshotApproximation instead.

current number of changes waiting to become effective

Overloaded snapshot returning derived type

Returns true if the topology information at the passed timestamp is already known

The most recently observed effective timestamp

The effective timestamp is sequencer_time + epsilon(sequencer_time), where epsilon is given by the topology change delay time, defined using the domain parameters.

This is the highest timestamp for which we can serve snapshots

Returns the topology information at a certain point in time

Fails with an exception if the state is not yet known.

Move the most known timestamp ahead in future based of newly discovered information

We don't know the most recent timestamp directly. However, we can guess it from two sources: What was the timestamp of the latest topology transaction added? And what was the last processing timestamp. We need to know both such that we can always deliver the latest valid set of topology information, and don't use old snapshots. Therefore, we expose the updateHead function on the public interface for initialisation purposes.