public List <T> Filter(ListItemFilterCallback <T> itemFilterCallback) { return(null); }
public bool Every(ListItemFilterCallback <T> itemFilterCallback) { return(false); }
public extern List <T> Filter(ListItemFilterCallback <T> itemFilterCallback);
public extern bool Some(ListItemFilterCallback <T> itemFilterCallback);
public extern bool Every(ListItemFilterCallback <T> itemFilterCallback);