anchor.diff:    }
   
     /**
  +  * @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
  -  //TODO handle arrays?
     */
     public any function to( required any email ) {
       addPersonalization(
  
positive.code: 
    /**
    * @hint Adds an additional 'to' recipient to the CURRENT personalization envelope
    //TODO handle arrays?
    */
    public any function addTo( required any email ) {
      var count = countPersonalizations();
  
negative.code: 
      setPersonalizations( [] );
      setContent( [] );
      setHeaders( {} );
  
      if ( arguments.keyExists( 'from' ) )
        this.from( from );
  