async function saveLanternNetworkData(devtoolsLog, outputPath) {
  /** @type {LH.Audit.Context} */
  // @ts-expect-error - the full audit context isn't needed for analysis.
  const context = {computedCache: new Map()};
  const networkAnalysis = await NetworkAnalysis.request(devtoolsLog, context);
  const lanternData = LoadSimulator.convertAnalysisToSaveableLanternData(networkAnalysis);

  fs.writeFileSync(outputPath, JSON.stringify(lanternData));
}
@param {LH.DevtoolsLog} devtoolsLog
@param {string} outputPath
@return {Promise<void>}