Function pipewire_sys::pw_filter_add_port

pub unsafe extern "C" fn pw_filter_add_port(
    filter: *mut pw_filter,
    direction: spa_direction,
    flags: pw_filter_port_flags,
    port_data_size: usize,
    props: *mut pw_properties,
    params: *mut *const spa_pod,
    n_params: u32
) -> *mut c_void

add a port to the filter, returns user data of port_data_size.