Add Executor and RelaySet

lib/RelaySet.ts

@@ -0,0 +1,24 @@
+import type {Relay} from './Relay'
+import {EventBus} from './util/EventBus'
+
+export class RelaySet {
+  relays: Relay[]
+  bus: EventBus
+  constructor(relays) {
+    this.relays = relays
+    this.bus = new EventBus()
+
+    relays.forEach(relay => {
+      relay.bus.pipe(EventBus.ANY, this.bus)
+    })
+  }
+  send(...payload) {
+    this.relays.forEach(async relay => {
+      await relay.connect()
+
+      if (relay.status === Relay.STATUS.READY) {
+        relay.send(...payload)
+      }
+    })
+  }
+}