src/server/pfs/server/obj_block_api_server.go
func (s *objBlockAPIServer) splitKey(key string) string {
	gen := s.getGeneration()
	if len(key) < prefixLength {
		return fmt.Sprintf("%s.%d", key, gen)
	}
	return fmt.Sprintf("%s.%s.%d", key[:prefixLength], key[prefixLength:], gen)
}
func (s *objBlockAPIServer) splitKey(key string) string {
	gen := s.getGeneration()
	if len(key) < prefixLength {
		return fmt.Sprintf("%s.%d", key, gen)
	}
	return fmt.Sprintf("%s.%s.%d", key[:prefixLength], key[prefixLength:], gen)
}
// splitKey splits a key into the format we want, and also postpends
// the generation number