Function parseRetryAfter

parseRetryAfter(
value: string | null | undefined,
nowMs: number,
): number | undefined
Reads Retry-After as milliseconds: delta-seconds or an HTTP date (IMF-fixdate).
Parameters
- value: string | null | undefined
  The header value.
- nowMs: number
  The current wall time, Unix milliseconds, for an HTTP date.
Returns number | undefined
The wait, never negative, or undefined when absent or unreadable.