Timed
An idempotent flow that needs to be replayed if it does not complete within a certain timeout.
Example use would be the notary client flow: if the client sends a request to an HA notary cluster, it will get accepted by one of the cluster members, but the member might crash before returning a response. The client flow would be stuck waiting for that member to come back up. Retrying the notary flow will re-send the request to the next available notary cluster member.
Note that any sub-flows called by a TimedFlow are assumed to be IdempotentFlow and will NOT have checkpoints persisted. Otherwise, it wouldn't be possible to correctly reset the TimedFlow. An implication of this is that idempotent flows must not only return the same final result of the flow, but if a flow returns multiple messages the full set of messages must be returned on subsequent attempts in the same order as the first flow.
An example of this would be if a notary returns an ETA message at any point, then any subsequent retries of the flow must also send such a message before returning the actual notarisation result.