I am building a fastify server to upload/download files to s3, when I want to download a file I am able to get it using a node stream and return it, so I prevent loading the whole file in memory, I would like to do something like:

• get the file web stream from the bucket
• scan it using clamAV, streaming data into the AV
  return the file stream to client only if the file is not infected

I have tried with piplines but I need to to check when the scan is done, and after I send the stream from s3 to the AV, the original stream is consumed, hence, I cannot send it to the client.
do you guys have any suggestion or any gotcha here?

code I have right now:

const stream = body.transformToWebStream();

const antivirusPassthrough = app.avClient.passthrough();
const downloadPassthrough = new PassThrough();


antivirusPassthrough.once("error", (err) => {
  throw err
});
antivirusPassthrough.once("scan-complete", (result) => {
  const { isInfected } = result;
  if (isInfected) {
    throw new Errpr("File is infected");
  }
});


pipeline(
  stream,
  antivirusPassthrough,
  downloadPassthrough,
  (err) => {
    if (err) {
      app.log.error(err);
    }
  }
);
return reply.send(downloadPassthrough);