While working on #1576, I found that ChunkedDecodingStreamFilter::transform() always consumes the whole input buffer (as reported by ::getBytesProcessed()) regardless of how much is consumed by the downstream filter (i.e. ::getDelegate()->transform()). This also applies to GZipDecodingStreamFilter.

This is incompatible with segment download since the filter is not aware of when the underlying segment completes downloading and, thus, results in data loss and corrupt download.

I shall submit a pull request to fix it in order to support segmented download with the above filters as transfer encodings.