EventsByTag(String, Int64) is used for retrieving events that were marked with a given tag, e.g. all events of an Aggregate Root type.

To tag events you create an IEventAdapter that wraps the events in a Tagged with the given `tags`.

You can retrieve a subset of all events by specifying offset, or use `0L` to retrieve all events with a given tag. The offset corresponds to an ordered sequence number for the specific tag. Note that the corresponding offset of each event is provided in the EventEnvelope, which makes it possible to resume the stream at a later point from a given offset.

In addition to the offset the EventEnvelope also provides `persistenceId` and `sequenceNr` for each event. The `sequenceNr` is the sequence number for the persistent actor with the `persistenceId` that persisted the event. The `persistenceId` + `sequenceNr` is an unique identifier for the event.

The returned event stream is ordered by the offset (tag sequence number), which corresponds to the same order as the write journal stored the events. The same stream elements (in same order) are returned for multiple executions of the query. Deleted events are not deleted from the tagged event stream.

The stream is not completed when it reaches the end of the currently stored events, but it continues to push new events when new events are persisted. Corresponding query that is completed when it reaches the end of the currently stored events is provided by CurrentEventsByTag(String, Int64).

The SQL write journal is notifying the query side as soon as tagged events are persisted, but for efficiency reasons the query side retrieves the events in batches that sometimes can be delayed up to the configured `refresh-interval`.

The stream is completed with failure if there is a failure in executing the query in the backend journal.

public Source<EventEnvelope, NotUsed> EventsByTag(
	string tag,
	long offset
)

abstract EventsByTag : 
        tag : string * 
        offset : int64 -> Source<EventEnvelope, NotUsed> 
override EventsByTag : 
        tag : string * 
        offset : int64 -> Source<EventEnvelope, NotUsed>