* - Synchronous: commands emitted by the client to which a reply is expected
* (e.g. subscribing/unsubscribing to conditions),
* - Asynchronous: notifications which are sent by the lttng_endpoint to the
* - Synchronous: commands emitted by the client to which a reply is expected
* (e.g. subscribing/unsubscribing to conditions),
* - Asynchronous: notifications which are sent by the lttng_endpoint to the