static _headersDictToHeadersArray(headersDict) {
    const result = [];
    for (const name of Object.keys(headersDict)) {
      const values = headersDict[name].split('\n');
      for (let i = 0; i < values.length; ++i) {
        result.push({name: name, value: values[i]});
      }
    }
    return result;
  }
Based on DevTools NetworkManager.
@see https://github.com/ChromeDevTools/devtools-frontend/blob/3415ee28e86a3f4bcc2e15b652d22069938df3a6/front_end/sdk/NetworkManager.js#L285-L297
@param {LH.Crdp.Network.Headers} headersDict
@return {Array<HeaderEntry>}