This function returns the change, in pixels, of the position of the player’s
Mouse in the last rendered frame as a
DataType/Vector2. This function only works if the mouse has been locked using the
UserInputService.MouseBehavior property. If the mouse has not been locked, the returned
DataType/Vector2 values will be zero.
The sensitivity of the mouse, determined in the client’s settings and
UserInputService/MouseDeltaSensitivity, will influence the result.
UserInputService is client-side only, this function can only be used in a
Change in movement of the mouse