public int getDelay(int n) {
        int delay = -1;
        if ((n >= 0) && (n < header.frameCount)) {
            delay = header.frames.get(n).delay;
        }
        return delay;
    }
Gets display duration for specified frame.

@param n int index of frame.
@return delay in milliseconds.
core/src/main/java/com/bumptech/glide/gifdecoder/GifDecoder.java