VertexCache will destroy the consistency of raft

[cangfengzhs]

1. When reading data from VertexCache, it does not check whether the current part is the leader.

2. When the leader transLeader from part A to part B, and then transLeader to part A, the data in the cache and the data in kvstore may be different
   

3. When insert/update and read are executed concurrently, vertexCache may hold older data, which is different from that in kvstore.
   

[critical27]

👍 , long history, you could replace it with row cache later.