+ * @param eventName
+ * The name of the event to enable
+ * @param loglevel
+ * The loglevel, will be passed as-is to lttng. May be null to
+ * not specify it.
+ * @param loglevelOnly
+ * True to use this log level only (--loglevel-only), or false to
+ * include all more severe levels (--loglevel). Ignored if
+ * "loglevel" is null.
+ * @param filter
+ * The filter string, may be null to not specify one.
+ * @return If the command executed successfully (return code = 0)