anchor.diff:  
   const String STOMP_EOF = '\x00';
   
  +/**
  + * Definition of a STOMP frame. 
  + * 
  + * All frames sent back and forth between the server and the client conforms to the structure defined by this class. 
  + */
   class Frame {
     final String command;
     final Map headers;
     final String body;
     
   
  +  /**
  +   * Creates a new instance of Frame. All arguments must be non-null.
  +   */
     Frame(this.command, this.headers, this.body) {
   
       if(this.headers == null) {
  
positive.code:     return lines.join("\n");
    }
  
    static Frame unmarshallSingle(String data) {
      /**
       * search for 2 consecutives LF byte to split the command
  
negative.code:     return frames;
    }
  
    /**
     * Marshal a Frame into a String from command and optionally headers and body.
     */
    static String marshall(String command, {Map headers, String body:""}) {
      if(headers == null) {
        headers = {};
  