Function aeron_async_remove_subscription 

pub unsafe extern "C" fn aeron_async_remove_subscription(
    registration_id: i64,
    client: *mut aeron_t,
    on_complete: aeron_notification_t,
    on_complete_clientd: *mut c_void,
) -> c_int

Asynchronously remove a subscription. If there is an aeron_subscription_t object for that subscription, it will get closed and freed.

@param registration_id of the subscription to be removed. @param client which owns the subscription. @param on_complete optional callback to execute once the subscription has been removed. This may happen on a separate thread, so the caller should ensure that clientd has the appropriate lifetime. Use NULL if not needed. @param on_complete_clientd parameter to pass to the on_complete callback. @return 0 for success or -1 for error.