/// <summary>
/// Register a named entity type by defining the <see cref="Actor.Props"/> of the entity actor and
/// functions to extract entity and shard identifier from messages. The <see cref="Sharding.ShardRegion"/>
/// actor for this type can later be retrieved with the <see cref="ShardRegion"/> method.
/// </summary>
/// <param name="typeName">The name of the entity type</param>
/// <param name="entityProps">
/// The <see cref="Actor.Props"/> of the entity actors that will be created by the <see cref="Sharding.ShardRegion"/>
/// </param>
/// <param name="settings">Configuration settings, see <see cref="ClusterShardingSettings"/></param>
/// <param name="messageExtractor">
/// Functions to extract the entity id, shard id, and the message to send to the entity from the incoming message.
/// </param>
/// <param name="allocationStrategy">Possibility to use a custom shard allocation and rebalancing logic</param>
/// <param name="handOffMessage">
/// The message that will be sent to entities when they are to be stopped for a rebalance or
/// graceful shutdown of a <see cref="Sharding.ShardRegion"/>, e.g. <see cref="PoisonPill"/>.
/// </param>
/// <returns>The actor ref of the <see cref="Sharding.ShardRegion"/> that is to be responsible for the shard.</returns>
public Task <IActorRef> StartAsync(string typeName, Props entityProps, ClusterShardingSettings settings,
IMessageExtractor messageExtractor, IShardAllocationStrategy allocationStrategy, object handOffMessage)
{
ExtractEntityId extractEntityId = messageExtractor.ToExtractEntityId();
ExtractShardId extractShardId = messageExtractor.ShardId;
return(StartAsync(typeName, entityProps, settings, extractEntityId, extractShardId, allocationStrategy, handOffMessage));
}