BroadcastCheckpointDiff updates the total written size of each table.

BroadcastEndTask sets the current task status to completed.

BroadcastError sets the error message of a table.

BroadcastInitProgress sets the total size of each table.

BroadcastStartTask sets the current task status to running.

BroadcastTableCheckpoint updates the checkpoint of a table.

BroadcastTableProgress updates the progress of a table.

EnableCurrentProgress init current progress struct on demand.

MarshalTableCheckpoints returns the checkpoint of a table in JSON format.

MarshalTaskProgress returns the current progress in JSON format.

Res is the web resources.