private BitmapRequestBuilder<ModelType, TranscodeType> downsample(Downsampler downsampler) {
        this.downsampler = downsampler;
        imageDecoder = new StreamBitmapDecoder(downsampler, bitmapPool, decodeFormat);
        super.decoder(new ImageVideoBitmapDecoder(imageDecoder, videoDecoder));
        return this;
    }
Load images using the given {@link Downsampler}. Replaces any existing image decoder. Defaults to
{@link Downsampler#AT_LEAST}. Will be ignored if the data represented by the model is a video. This replaces any
previous calls to {@link #imageDecoder(ResourceDecoder)}  and {@link #decoder(ResourceDecoder)} with default
decoders with the appropriate options set.

@see #imageDecoder

@param downsampler The downsampler.
@return This request builder.
core/src/main/java/com/bumptech/glide/BitmapRequestBuilder.java