public Optional<EventStreamInfo> getSubcribeEventStreamInfo(ToShapeId operation) {
        return Optional.ofNullable(subscribeInfo.get(operation.toShapeId()));
    }
Get subscribe event stream info.

<p>This information describes if the event stream contains a single
event, multiple events, and if there are any initial-request or
response members.

@param operation Operation to get the event stream info o.
@return Returns the optionally found event stream info.
smithy-mqtt-traits/src/main/java/software/amazon/smithy/mqtt/traits/ResolvedTopicIndex.java