To clarify, "unicode" was replaced with "unf" to so it'll work with MRI and JRuby.  But it was actually the compiled extension for MRI that pushed us towards not making it a hard dependency, since it's only needed for AWS and a lot of fog users don't use AWS.  Both "unicode" and "unf" have a compiled extension for MRI.  If you know of a pure Ruby variant, that would be fantastic.