Legend.addItemTextMarker Method
        
 Adds a legend item to the legend.
 
         
        Parameters
        
            - ownerId
            
 
            - 
                
Type: Object
 The ID of the owner of this legend item.
  
            - id
            
 
            - 
                
Type: Object
 The ID of this legend item.
  
            - itemText
            
 
            - 
                
Type: String
 The text of the legend item.
  
            - markerShape
            
 
            - 
                
Type: MarkerSymbol
 The marker that this legend item will use.