Accepts timeouts, network errors, and status codes 408, 429, 500, 502, 503, and 504. Other errors are rejected.

Assumes the operation is safe to repeat: a timeout does not mean a write failed. Does not account for Retry-After, since Http.Error does not retain headers.

Keep the body of a successful response, or turn a failed response into an Http.Error. Use with Http.stringResolver or Http.bytesResolver.