How to save an actix multipart field to s3 using rusoto_s3?

Question

Im completely new to rust, but learning. I am attempting to take a multipart upload using actix_web and actix_multipart and upload it to aws s3 using rusoto_s3. From my basic undersntaing basically i have a stream of one type that i need to convert into a ByteStream which is what put_object PutObjectRequest { body } is requiring.

I presume i need to use map on the field to convert it from one type to another, but I'm a little lost.

E.g Something along these lines?

pub fn save_file_s3(field: Field, s3_client: &S3Client) {
    let bucket = env::var("S3_BUCKET").expect("S3 bucket must be set.");

    let item = field.map();

    s3_client.put_object(PutObjectRequest {
        bucket: bucket,
        body: item,        
        ..Default::default()
    }).into_stream();
}

Thanks for the help!