Doesn't attempt to create the KV stream if it doesn't exist.
allow_direct: boolean
If true and on a recent server, changes the way the KV
retrieves values. This option is significantly faster,
but has the possibility of inconsistency during a read.
optional
metadata: Record<string, string>
Metadata field to store additional information about the kv. Note that
keys starting with _nats are reserved. This feature only supported on servers
2.10.x and better.