FDateTime::ParseHttpDate

Parses a date string in HTTP-date format (rfc1123-date | rfc850-date | asctime-date) [https://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3.1](https://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3.1)