@Suspendable @JvmOverloads fun sendAll(payload: Any, sessions: Set<FlowSession>, maySkipCheckpoint: Boolean = false): Unit
Queues the given payload for sending to the provided sessions and continues without suspending.
Note that the other parties may receive the message at some arbitrary later point or not at all: if one of the provided sessions is offline then message delivery will be retried until the corresponding node comes back or until the message is older than the network's event horizon time.
payload - the payload to send.
sessions - the sessions to send the provided payload to.
maySkipCheckpoint - whether checkpointing should be skipped.