Sometimes named hooks inspection will seemingly fail the first time then work the second time. (e.g. using a DEV build of Facebook.com, the `<CometTheme>` component currently does this).

I _think_ this might indicate a timeout during inspection? (So the retry is fast because everything is cached.)
new SourceMapConsumer(JSON.parse(sourceMapContents)),
            );
          if (__DEBUG__) {
            if (!fetchPromises.has(url)) {
              console.log(
                `extractAndLoadSourceMaps() External source map "${url}"`,
              );
            }
          }
          fetchPromises.set(url, fetchPromise);
          setPromises.push(
            fetchPromise.then(sourceConsumer => {
              hookSourceData.sourceConsumer = sourceConsumer;
            }),
          );
          break;
        }
      }
    }
  });
  return Promise.all(setPromises);
}
function fetchFile(url: string): Promise<string> {
  return new Promise((resolve, reject) => {
    fetch(url).then(response => {
      if (response.ok) {
        response
          .text()
          .then(text => {
            resolve(text);