Animation must have a non-nil `value` before starting.

[Dami]

I get this error when I try to use this in swiftui: "Animation must have a non-nil value before starting."
my code is here:

`.onAppear {
offsetAnimator.value = .zero

        // The offset animator's callback will update the `offset` state variable.
        offsetAnimator.valueChanged = { newValue in
            boxOffset = newValue
        }
    }
    .offset(x: boxOffset.x, y: boxOffset.y)
    .gesture(
        DragGesture()
            .onChanged { value in
                // Update the animator's target to the new drag translation.
                offsetAnimator.target = CGPoint(x: value.translation.width, y: value.translation.height)

                // Don't animate the box's position when we're dragging it.
                offsetAnimator.mode = .nonAnimated
                offsetAnimator.start()
            }
            .onEnded { value in
                // Animate the box to its original location (i.e. with zero translation).
                offsetAnimator.target = .zero

                // We want the box to animate to its original location, so use an `animated` mode.
                // This is different than the
                offsetAnimator.mode = .animated

                // Take the velocity of the gesture, and give it to the animator.
                // This makes the throw animation feel natural and continuous.
                offsetAnimator.velocity = CGPoint(x: value.velocity.width, y: value.velocity.height)
                offsetAnimator.start()
            }
    )`

thank you for your help