Related to https://github.com/GoogleChrome/web-vitals/issues/137 Patch the SDK to not record negative TTFB measurements. <img width="454" alt="Screen Shot 2021-05-05 at 2 01 07 PM" src="https://user-images.githubusercontent.com/139499/117191877-15b50900-adaf-11eb-8aa4-5d6d5e45fcee.png">
