GMSMarkerLayer
@interface GMSMarkerLayer : GMSOverlayLayerGMSMarkerLayer is a subclass of GMSOverlayLayer, available on a per-marker basis, that allows
 animation of several properties of its associated GMSMarker.
Note that this CALayer is never actually rendered directly, as GMSMapView is provided
 entirely via an OpenGL layer. As such, adjustments or animations to ‘default’ properties of
 CALayer will not have any effect.
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                  Latitude, part of positiononGMSMarker.DeclarationSwift var latitude: CLLocationDegrees { get set }Objective-C @property (nonatomic) CLLocationDegrees latitude;
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                  Longitude, part of positiononGMSMarker.DeclarationSwift var longitude: CLLocationDegrees { get set }Objective-C @property (nonatomic) CLLocationDegrees longitude;
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                  Rotation, as per GMSMarker.DeclarationSwift var rotation: CLLocationDegrees { get set }Objective-C @property (nonatomic) CLLocationDegrees rotation;
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                  Opacity, as per GMSMarker.DeclarationSwift var opacity: Float { get set }Objective-C @property float opacity;