     /// An optional completion callback.
     internal var completionCallback: ((Bool) -> Void)?
     
-    /// A boolean indicating if the transition has finished.
-    internal var isFinishing = true
-    
     /// An Array of MotionPreprocessors used during a transition.
     internal lazy var preprocessors = [MotionPreprocessor]()
     

    /// Updates the animators.
    func updateAnimators() {
        let t = progress * totalDuration
        for a in animators {
            a.seek(to: t)
        }
    }
    
    /// Updates the plugins.
    func updatePlugins() {
        let t = progress * totalDuration
        for p in plugins where p.requirePerFrameCallback {
            p.seek(to: t)
        }
    }
}

        return isNavigationController || isTabBarController
    }
    
    /// Indicates whether the to view controller is full screen.
    internal var toOverFullScreen: Bool {
        return !isContainerController && (toViewController?.modalPresentationStyle == .overFullScreen || toViewController?.modalPresentationStyle == .overCurrentContext)
    }
    
    /// Indicates whether the from view controller is full screen.
    internal var fromOverFullScreen: Bool {
        return !isContainerController && (fromViewController?.modalPresentationStyle == .overFullScreen || fromViewController?.modalPresentationStyle == .overCurrentContext)
    }
    
    /// An initializer.
