If the container is not full (see {`High‐Water Mark` Feature}), append the specified item to the front of the container, otherwise leave the container unchanged. Return 0 if the container was updated and a non‐zero value otherwise.
If the container is not full (see {`High‐Water Mark` Feature}), append the specified item to the front of the container, otherwise leave the container unchanged. Return 0 if the container was updated and a non‐zero value otherwise.