message: Add telemetry for browser caching of blob
diff: @@ -349,12 +349,22 @@ export class OdspDocumentStorageService implements IDocumentStorageService {
  async (event) => {
  const res = await this.epochTracker.fetchResponse(url, { headers }, "blob");
  blob = await res.arrayBuffer();
  + const sprequestguid = res.headers.get("sprequestguid") ?? undefined;
  event.end({
  size: blob.byteLength,
  serverRetries: res.headers.get("x-fluid-retries") ?? undefined,
  waitQueueLength: this.epochTracker.rateLimiter.waitQueueLength,
  - sprequestguid: res.headers.get("sprequestguid") ?? undefined,
  + sprequestguid,
  });
  + const cacheControl = res.headers.get("cache-control") ?? undefined;
  + if (cacheControl === undefined || !(cacheControl.includes("private") || cacheControl.includes("public"))) {
  + this.logger.sendErrorEvent({
  + eventName: "NonCacheableBlob",
  + cacheControl,
  + blobId,
  + sprequestguid,
  + });
  + }
  return blob;
  },
  );
  