open method
void
open()
Opens the morph animation from the current position.
Resets the handoff latch and runs the spring toward 1.0 from rest.
Safe to call while the close animation is still running.
Implementation
void open() {
_isClosing = false;
_hasHandedOff = false;
_runSpring(1.0, velocityHint: 0.0);
}