Function motion 

pub fn motion() -> Motion

Create a motion container

The motion container automatically generates a stable unique key using UUID, ensuring uniqueness even when created in loops or closures.

For additional uniqueness in loops, use .id():

for i in 0..items.len() {
    motion()
        .id(i)  // Appends index to auto-generated key
        .fade_in(300)
        .child(item_content)
}