A crate in alpha with a futures::Sink for doing AWS S3 multipart uploads with the official SDK

Current:

• Upload: For the finite case, send items to Upload until they are exhausted or the (optional) target upload size is reached. Flushing or closing the sink completes the upload. Attempting to send more items after an upload is an error. For this reason, it's probably not a good idea to configure it with a target upload size, unless it's really a "maximum upload size" and a very safe upper bound on the total bytes.
  • The Upload sink can also start a new upload to address the write-after-upload error by calling poll_new_upload.