What is the best way to write a response from a HttpURLConnection inputStream in Javalin?

Question

i'm writing a simple API that read a file from a remote server and return it to the caller using Javalin.

This is my simple code:

class FileReader{
    public []byte getFileBytes(String fileURL){
       ...
       HttpURLConnection con = null;
       try {
          URL url = new URL(fileURL);
          con = (HttpURLConnection) url.openConnection();
          con.setRequestMethod("GET");

          ...

          int status = con.getResponseCode();
        
          if (status != 200) {
             //manage errors
          } else {
            return con.getInputStream().readAllBytes();
          }

      }catch(Exception e){
          //manage exceptions
      }finally {
          if(con != null) {
              con.disconnect();
          }
      }
    }
}

public void handle(Context ctx) throws Exception {
    ...

    []byte fileBytes = fileReader.getFileBytes("https://..../myfile");
    ctx.header(Header.CONTENT_TYPE, "application/octet-stream");
    ctx.result(fileBytes);
}

Everithing seems to be ok but the problem is that every file is first downloaded into memory before returning to the original caller. I was wondering if there are some more clever ways to do this, such as reading the bytes into a buffer (a chunk at a time) from the inputstream and write them in the javalin response so that the memory is only used for the chunk length... I couldn't find a way to do this.

Also, what I've seen is that javalin has a method ctx.result that takes an inputstream and I was hoping to try it and see if the memory used was less, but doing something like the following, results in a IOException "stream is closed" error

public void handle(Context ctx) throws Exception {
   HttpURLConnection con = null;
   try {
      URL url = new URL(fileURL);
      con = (HttpURLConnection) url.openConnection();
      con.setRequestMethod("GET");

      ...

      int status = con.getResponseCode();

      if (status != 200) {
         //manage errors
      } else {
        ctx.header(Header.CONTENT_TYPE, "application/octet-stream");
        ctx.result(con.getInputStream());
      }

  }catch(Exception e){
      //manage exceptions
  }finally {
      if(con != null) {
          con.disconnect();
      }
  }
}

If you have any hints or ideas i would be grateful. Thanks