Gets the UNIX file descriptors associated with this, if any.
This method is only available on UNIX.
The file descriptors normally correspond to g_variant_type_handle values in the body of the message. For example, if get_handle returns 5, that is intended to be a reference to the file descriptor that can be accessed by `g_unix_fd_list_get (list, 5, ...)`.
this |
A DBusMessage. |
A UnixFDList or null if no file descriptors are associated. Do not free, this object is owned by this. |