ISseService.peek(name: string): SseChannel | undefined
Returns the named channel if one already exists, without creating it.
The non-allocating counterpart to ISseService.channel. A
presence or dashboard endpoint that reports size for a name taken from a
request must use this: channel(name) would register one channel per
distinct name polled, and an SSE channel is never reclaimed before
shutdown.
SseChannel | undefined
The channel, or undefined when no channel of that name exists