    # File lib/merb-core/rack/stream_wrapper.rb, line 11
          def each(&callback)
            if Proc === @body
              @writer = lambda { |x| callback.call(x) }
              @body.call(self)
            elsif @body.is_a?(String)
              @body.each_line(&callback)
            elsif @body.nil?
              @body.to_s.each_line(&callback)
            elsif @body.is_a?(Integer)
              @body.to_s.each_line(&callback)
            else
              @body.each(&callback)
            end
          end