A `GUnixFDList` contains a list of file descriptors.
It owns the file descriptors that it contains, closing them when finalized.
It may be wrapped in a [`GUnixFDMessage`](../gio-unix/class.UnixFDMessage.html) and sent over a [class@Gio.Socket] in the
`G_SOCKET_FAMILY_UNIX` family by using [method@Gio.Socket.send_message] and received using [method@Gio.Socket.receive_message].
Before 2.74, `<gio/gunixfdlist.h>` belonged to the UNIX-specific GIO interfaces, thus you had to use the `gio-unix-2.0.pc`
pkg-config file when using it.