def content_type=(type)
      unless Merb.available_mime_types.has_key?(type)
        raise Merb::ControllerExceptions::NotAcceptable.new("Unknown content_type for response: #{type}") 
      end

      @_content_type = type

      mime = Merb.available_mime_types[type]
      
      headers["Content-Type"] = mime[:content_type]
      
      # merge any format specific response headers
      mime[:response_headers].each { |k,v| headers[k] ||= v }
      
      # if given, use a block to finetune any runtime headers
      mime[:response_block].call(self) if mime[:response_block]

      @_content_type
    end
def content_type=(type)
      unless Merb.available_mime_types.has_key?(type)
        raise Merb::ControllerExceptions::NotAcceptable.new("Unknown content_type for response: #{type}") 
      end

      @_content_type = type

      mime = Merb.available_mime_types[type]
      
      headers["Content-Type"] = mime[:content_type]
      
      # merge any format specific response headers
      mime[:response_headers].each { |k,v| headers[k] ||= v }
      
      # if given, use a block to finetune any runtime headers
      mime[:response_block].call(self) if mime[:response_block]

      @_content_type
    end
Sets the content type of the current response to a value based on
 a passed in key. The Content-Type header will be set to the first
 registered header for the mime-type.

 ==== Parameters
 type<Symbol>:: The content type.

 ==== Raises
 ArgumentError:: type is not in the list of registered mime-types.

 ==== Returns
 Symbol:: The content-type that was passed in.

 :api: plugin