http://www.rfc-editor.org/rfc/rfc3229.txt
RFC 3229: Delta encoding in HTTP, J. Mogul, B. Krishnamurthy, F. Douglis, A. Feldmann, Y. Goland, A. van Hoff, D. Hellerstein2002-01-01T23:00:00-00:00This document describes how delta encoding can be supported as a compatible extension to HTTP/1.1. [STANDARDS-TRACK]