'Handle HTTP HEAD request.'

@public
@timing_stats()
def HEAD(self, req):

    (drive, part, account) = split_and_validate_path(req, 3)
    out_content_type = get_listing_content_type(req)
    if (self.mount_check and (not check_mount(self.root, drive))):
        return HTTPInsufficientStorage(drive=drive, request=req)
    broker = self._get_account_broker(drive, part, account, pending_timeout=0.1, stale_reads_ok=True)
    if broker.is_deleted():
        return self._deleted_response(broker, req, HTTPNotFound)
    headers = get_response_headers(broker)
    headers['Content-Type'] = out_content_type
    return HTTPNoContent(request=req, headers=headers, charset='utf-8')
