@Override
        public ModelLoader<String, ParcelFileDescriptor> build(Context context, GenericLoaderFactory factories) {
            return new FileDescriptorStringLoader(factories.buildModelLoader(Uri.class, ParcelFileDescriptor.class));
        }
The default factory for {@link FileDescriptorStringLoader}s.
core/src/main/java/com/bumptech/glide/load/model/file_descriptor/FileDescriptorStringLoader.java