`Connect` returns a connection and client to remote store.

CreateTiStore creates a tikv storage client Note: It will return a same storage if the urls connect to a same pd cluster, so must be careful when you call storage.Close().

GetSnapshotMeta returns tidb meta information TODO: move it to a correct package.

NewSubscriptionClient creates a client.

StatusIsEOF checks whether status is caused by client send closing.

SubscriptionClient is used to subscribe events of table ranges from TiKV.

subscriptionID is a unique identifier for a subscription.