NameError with s3_file as a full fledged resource/provider loaded from the cookbook's libraries folder

libraries_s3_file.rb

class Chef
  class Resource
    class S3
      class File < Chef::Resource

        def initialize(name, run_context=nil)
          super
          @resource_name = :s3_file
          @provider = Chef::Provider::S3::File
          @action = :create
        end

      end
    end
  end
end

recipes_default.rb

s3_file '/tmp/myfile.tar.gz' do
  remote_path '/api/myfile.tar.gz'
  bucket 'mybucket'
  aws_access_key_id 'ACCESS_KEY'
  aws_secret_access_key 'SECRET_KEY'
  mode '0644'
  action :create
end