events: add a generic DHT event. (#154)

event/dht.go

+package event
+
+// RawJSON is a type that contains a raw JSON string.
+type RawJSON string
+
+// GenericDHTEvent is a type that encapsulates an actual DHT event by carrying
+// its raw JSON.
+//
+// Context: the DHT event system is rather bespoke and a bit messy at the time,
+// so until we unify/clean that up, this event bridges the gap. It should only
+// be consumed for informational purposes.
+//
+// EXPERIMENTAL: this will likely be removed if/when the DHT event types are
+// hoisted to core, and the DHT event system is reconciled with the eventbus.
+type GenericDHTEvent struct {
+	// Type is the type of the DHT event that occured.
+	Type string
+
+	// Raw is the raw JSON representation of the event payload.
+	Raw RawJSON
+}