good practice to upload file to s3 using nodejs scalability and perfomance should be considered

i have using multer to upload file in s3 and i have tried three methods to upload a file to s3

1. memoryStorage(default)
2. *custom S3stroage engine(by directly straming the file from request and uploading to s3)
3. Diskstroage(default)

in my case the second approach is good in perfomance wise but i think its not scalable that much.but second method saves lots of time(instead of writing to disk and then streaming from there its much more stright forward).but i dont know what will the cons of this approach.can any one suggest me a good approach.

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