How to Get File Size in onUpload with Convex R2 When getMetadata Returns Null?

export const { generateUploadUrl, syncMetadata } = r2.clientApi({
  checkUpload: async (ctx, bucket) => {
    const user = await ctx.runQuery(api.users.current);
    if (!user) {
      throw new ConvexError("unauthorized");
    }
    // TODO: check if the storage is full
  },
  onUpload: async (ctx, key) => {
    // Problem: metadata is null here
    const metadata = await r2.getMetadata(ctx, key);
    console.log("Metadata in onUpload:", metadata);

    const user = await ctx.runQuery(api.users.current);
    if (!user || !metadata) {
      return;
    }

    await totalStorageAggregate.insert(ctx, {
      key: user._id,
      id: key,
      sumValue: metadata.size, // metadata.size would be undefined if metadata is null
    });
  },
  onDelete: async (ctx, key) => {
    const user = await ctx.runQuery(api.users.current);
    if (!user) {
      throw new ConvexError("unauthorized");
    }

    await totalStorageAggregate.delete(ctx, {
      key: user._id,
      id: key,
    });
  },
});