Enum describing different modes for syncing a stream.
Do not query pubsub for the new tip in any circumstance. This means that if the stream is not in cache or the pin store, then only the genesis commit for the stream will be returned
If the stream is found in the node's in-memory cache or pin store, then return the cached version without performing any query to the pubsub network for the current tip.
Always query pubsub for the current tip for the stream and wait up to 'syncTimeoutSeconds' for the response, regardless of whether or not the stream is found in the node's cache