PersistentShardCoordinator initiates rebalancing process by sending this message to all registered ShardRegion actors (including proxy only). They are supposed to discard their known location of the shard, i.e. start buffering incoming messages for the shard. They reply with PersistentShardCoordinatorBeginHandOffAck. When all have replied the PersistentShardCoordinator continues by sending PersistentShardCoordinatorHandOff to the ShardRegion responsible for the shard.

[SerializableAttribute]
public sealed class BeginHandOff : PersistentShardCoordinatorICoordinatorMessage, 
	IClusterShardingSerializable

[<SealedAttribute>]
[<SerializableAttribute>]
type BeginHandOff =  
    class
        interface PersistentShardCoordinatorICoordinatorMessage
        interface IClusterShardingSerializable
    end