rackspace/php-opencloud — pull request #265 by reviling (2014-01-05 06:00:05+00:00)
Title: Changing Metadata array to use proper header syntax in DataObject's update().

Needed to convert the metadata names in to something like X-Meta-Object-... otherwise the metadata will be ignored by Rackspace Cloud Files.

AbstractResource's saveMetadata works this way already.