The KVClientTable (and also other tables) is not copy/move-save.

[Yuzhen11]

Copy:
KVClientTable should not be copied, so the copy constructor and copy assignment operator should be disable.
Move:
Ideally, KVClientTable can be moved. But actually it is not the case. If we move a table, the recv_kvs_ in kv_table_box is also moved. However, the original recv_kvs_ was captured and registered into the callback_runner_ which will store the get requests. The moved recv_kvs_ will not receive the get requests.