docker/docker-registry — pull request #848 by stevvooe (2014-12-13 01:47:43+00:00)
Title: Relax requirement for size argument during blob upload

During client implementation, it was found that requiring the size argument
made client implementation more complex. The original benefit of the size
argument was to provide an additional check alongside of tarsum to validate
incoming data. For the purposes of the registry, it has been determined that
tarsum should be enough to validate incoming content.

At this time, the size check is optional but we may consider removing it
completely.