a `103 Early Hints` response. For entries created by the built-in `fetch()`

implementation, this is currently `0` because interim response timings are not recorded.

The render blocking status of the resource. It is either `'blocking'` or

`'non-blocking'`. Entries created by the built-in `fetch()` implementation

return `'non-blocking'`.

string if it cannot be determined. Entries created by the built-in `fetch()`

implementation currently return an empty string.

The content encoding, such as `'gzip'` or `'br'`, that was applied to the

fetched resource, or an empty string if none was applied or it cannot be

determined. Entries created by the built-in `fetch()` implementation currently

return an empty string.