anchor.diff:  
     /**
     * @hint Adds an additional 'to' recipient to the CURRENT personalization envelope
  -  //TODO handle arrays?
     */
     public any function addTo( required any email ) {
       var count = countPersonalizations();
  
positive.code: 
      setPersonalizations( [] );
      setContent( [] );
  
      if ( arguments.keyExists( 'from' ) )
        this.from( from );
  
negative.code:   }
  
    /**
    * @hint Adds a single header to the global message. This can be overridden by a personalized header. You can set a header by providing the header and value, or by passing in a struct.
    * @header Facilitates two means of setting a header. You can pass in a struct with a key/value pair for the name and value of the header. Alternativaly, you can use this to pass in the name of the header, and provide the value as a second argument.
    */
    public any function header( any header, any value ) {
      if ( isStruct( header ) )
        variables.headers.append( header );
      else
        variables.headers[ header ] = value;
  
      return this;
    }
  
    /**
    * @hint Adds a NEW personalization envelope, with only the specified email address. The personalization can then be further customized with later commands
    */
    public any function to( required any email ) {
      addPersonalization(
  