dispose method
void
dispose()
Implementation
void dispose() {
_animator?.cancel();
_releaseListener();
_lockMap[viewId] = false;
_streetViewPanorama.options = gmaps.StreetViewPanoramaOptions()
//set to invisible
..visible = false
// reset control setting
..position = null
..pano = null
..showRoadLabels = true
..clickToGo = true
..addressControl = true
..disableDefaultUI = true
..disableDoubleClickZoom = false
..enableCloseButton = false
..fullscreenControl = true
..linksControl = true
..motionTracking = true
..motionTrackingControl = true
..scrollwheel = true
..panControl = true
..zoomControl = true
..pov = (gmaps.StreetViewPov()
..heading = 0
..pitch = 0)
..zoom = 1;
}