public long[] getKeyTimes() {
        Set<Long> keyFrameTimesSet = new HashSet<>();
        for (FbxAnimCurveNode curveNode : animCurves.values()) {
            for (FbxAnimCurve curve : curveNode.getCurves()) {
                for (long keyTime : curve.getKeyTimes()) {
                    keyFrameTimesSet.add(keyTime);
                }
            }
        }
        long[] keyFrameTimes = new long[keyFrameTimesSet.size()];
        int i = 0;
        for (Long keyFrameTime : keyFrameTimesSet) {
            keyFrameTimes[i++] = keyFrameTime;
        }
        Arrays.sort(keyFrameTimes);
        return keyFrameTimes;
    }
Maps animation stacks to influenced nodes. 
Will be used later to create jME3 tracks.
jme3-plugins/src/fbx/java/com/jme3/scene/plugins/fbx/anim/FbxToJmeTrack.java