code: public void sendResponse(int code, String response) {
          if(con.isClosed()) return;
  
          if(response == null || response.isEmpty()) {
              response = "Unknown";
          }
  
          try {
              if(response.charAt(0) == '-') {
                  writer.write(code + response + "\r\n");
              } else {
                  writer.write(code + " " + response + "\r\n");
              }
              writer.flush();
          } catch(IOException ex) {
              Utils.closeQuietly(this);
          }
          responseSent = true;
      }
docs: Sends a response to the connection
  @param code The response code
  @param response The response message