Clients indicate support for the extension by requesting a capability server-time
as per the [IRC Client Capabilities Extension][caps].
CAP REQ :server-time
After requesting the capability, clients MUST be able to parse an optional timestamp at the start of each message. The message pseudo-BNF, as defined in [RFC 1459, section 2.3.1][rfc1459] is extended to look as follows:
::= ['@' ] [':' ]