Nickname of the user the enqueueing event relates to.
Whether to actually issue WHOIS queries at all or just enqueue.
Whether or not to issue queries as low-priority background messages.
Exception if a success of failure function was to trigger in an impossible scenario, such as on WHOIS results on Twitch.
Constructs a CarryingFiber carrying a IRCEvent and enqueues it into the IRCPluginState.awaitingFibers
associative array, then issues a WHOIS query (unless overridden via the issueWhois parameter).