Computes the effective timestamps of topology transactions

Transaction validation and processing depends on the topology state at the given sequencing time. If topology transactions became effective immediately, we would have to inspect every event first if there is a topology state and wait until all the topology processing has finished before evaluating the transaction. This would cause a sequential bottleneck.

To avoid this bottleneck, topology transactions become effective only in the future at an "effective time", where effective time >= sequencingTime + synchronizerParameters.topologyChangeDelay.

However, the synchronizerParameters can change and so can the topologyChangeDelay. So it is non-trivial to apply the right topologyChangeDelay. Also, if the topologyChangeDelay is decreased, the effective timestamps of topology transactions could "run backwards", which would break topology management.

This class computes the effective timestamps of topology transactions from their sequencing timestamps. It makes sure that effective timestamps are strictly monotonically increasing. For better performance, it keeps the current as well as all future topologyChangeDelays in memory, so that all computations can be performed without reading from the database.