def METHOD_NAME(fd):
    """
    Some file descriptors may be closed 'silently' - that is, by the garbage
    collector, by an external library, etc. When the OS returns a file descriptor
    from an open call (or something similar), this may be the only indication we
    have that the FD has been closed and then recycled.
    We let the hub know that the old file descriptor is dead; any stuck listeners
    will be disabled and notified in turn.
    """
    hub = get_hub()
    hub.mark_as_reopened(fd)