Shotgun with Ruby 1.9.1

[beenimble]

Hello, does anybody have Shotgun working with Ruby 1.9.1? I get the
following error when I try a simple request:

Rack::Lint::LintError at /
rack.input #<StringIO:0x00000100d03dc8> does not have ASCII-8BIT as
its external encoding

I can see where the encoding's being returned as UTF-8, but I've been
unable to set it in various attempts (such as specifying
Encoding.default_external).

Running my test app via rackup or thin works fine.

Thanks.