The sidecar provides a block delivery service to clients such as FSC nodes. For example, an FSC node can periodically publish transaction IDs of interest to the sidecar so that it can receive complete data about the transaction when it is committed or aborted. When a sidecar fails and restarts, the FSC node should assume that no state is persisted at the sidecar and, therefore, needs to resubmit the transaction IDs of interest for which it has not yet received a status update.