in shimmer/src/main/java/com/facebook/shimmer/ShimmerDrawable.java [50:60]
public void setShimmer(@Nullable Shimmer shimmer) {
mShimmer = shimmer;
if (mShimmer != null) {
mShimmerPaint.setXfermode(
new PorterDuffXfermode(
mShimmer.alphaShimmer ? PorterDuff.Mode.DST_IN : PorterDuff.Mode.SRC_IN));
}
updateShader();
updateValueAnimator();
invalidateSelf();
}