track method
Tracks a new blob URL for a model file.
If a blob URL already exists for this filename, revokes the old one first.
Implementation
void track(String filename, String blobUrl) {
// Clean up old blob URL if exists
final oldUrl = _activeBlobUrls[filename];
if (oldUrl != null) {
_jsInterop.revokeBlobUrl(oldUrl);
}
_activeBlobUrls[filename] = blobUrl;
}