    # File lib/mongrel/handlers.rb, line 193
        def send_file(req_path, request, response, header_only=false)

          stat = File.stat(req_path)

          # Set the last modified times as well and etag for all files
          mtime = stat.mtime
          # Calculated the same as apache, not sure how well the works on win32
          etag = Const::ETAG_FORMAT % [mtime.to_i, stat.size, stat.ino]

          modified_since = request.params[Const::HTTP_IF_MODIFIED_SINCE]
          none_match = request.params[Const::HTTP_IF_NONE_MATCH]

          # test to see if this is a conditional request, and test if
          # the response would be identical to the last response
          same_response = case
                          when modified_since && !last_response_time = Time.httpdate(modified_since) rescue nil : false
                          when modified_since && last_response_time > Time.now                                  : false
                          when modified_since && mtime > last_response_time                                     : false
                          when none_match     && none_match == '*'                                              : false
                          when none_match     && !none_match.strip.split(/\s*,\s*/).include?(etag)              : false
                          else modified_since || none_match  # validation successful if we get this far and at least one of the header exists
                          end

          header = response.header
          header[Const::ETAG] = etag

          if same_response
            response.start(304) {}
          else

            # First we setup the headers and status then we do a very fast send on the socket directly

            # Support custom responses except 404, which is the default. A little awkward.
            response.status = 200 if response.status == 404
            header[Const::LAST_MODIFIED] = mtime.httpdate

            # Set the mime type from our map based on the ending
            dot_at = req_path.rindex('.')
            if dot_at
              header[Const::CONTENT_TYPE] = MIME_TYPES[req_path[dot_at .. -1]] || @default_content_type
            else
              header[Const::CONTENT_TYPE] = @default_content_type
            end

            # send a status with out content length
            response.send_status(stat.size)
            response.send_header

            if not header_only
              response.send_file(req_path, stat.size < Const::CHUNK_SIZE * 2)
            end
          end
        end