Read Progress Stream

Wrap a futures stream and report bytes so that uploading files can indicate progress.

To see an example progress bar run:

cargo test -- --nocapture

lib.rs:

Wrapper for a stream that stores the number of bytes read so that uploading to S3 using the rusoto_s3 crate can indicate upload progress for larger files.

See the test for example usage and run with --nocapture to see the mock progress bar:

cargo test -- --nocapture