refactor: share extension deferred and runtime helpers

extensions/shared/channel-status-summary.ts

@@ -8,6 +8,11 @@ type PassiveChannelStatusSnapshot = {
   lastProbeAt?: number | null;
 };
 
+type TrafficStatusSnapshot = {
+  lastInboundAt?: number | null;
+  lastOutboundAt?: number | null;
+};
+
 export function buildPassiveChannelStatusSummary<TExtra extends object>(
   snapshot: PassiveChannelStatusSnapshot,
   extra?: TExtra,
@@ -32,3 +37,12 @@ export function buildPassiveProbedChannelStatusSummary<TExtra extends object>(
     lastProbeAt: snapshot.lastProbeAt ?? null,
   };
 }
+
+export function buildTrafficStatusSummary<TSnapshot extends TrafficStatusSnapshot>(
+  snapshot?: TSnapshot | null,
+) {
+  return {
+    lastInboundAt: snapshot?.lastInboundAt ?? null,
+    lastOutboundAt: snapshot?.lastOutboundAt ?? null,
+  };
+}

extensions/shared/deferred.ts

@@ -0,0 +1,9 @@
+export function createDeferred<T>() {
+  let resolve!: (value: T | PromiseLike<T>) => void;
+  let reject!: (reason?: unknown) => void;
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  return { promise, resolve, reject };
+}