protected void encodeIndexedId(FacesContext context, UIComponent component, int index) throws IOException {
        ComponentUtils.encodeIndexedId(context, component, index);
    }
GitHub #7763 Renders an in memory UIComponent and updates its ID with an index.
For example id="form:test" becomes id="form:test:0".

@param context the {@link FacesContext}.
@param component the {@link UIComponent} to render.
@param index the index number to append to the ID
@throws IOException if an input/ output error occurs.
primefaces/src/main/java/org/primefaces/renderkit/CoreRenderer.java