uniqueKey method
Returns a unique tag for this event that you can use to identify it.
Implementation
NostrEventKey uniqueKey() {
assert(
subscriptionId != null,
"This event is created by you, "
"so it doesn't have a subscription id, "
"this ùmethod is meant for events that are received from the relays.");
return NostrEventKey(
eventId: id,
sourceSubscriptionId: subscriptionId!,
originalSourceEvent: this,
);
}