async Task PurgeOrchestrationHistorySegmentAsync(
TableQuerySegment <OrchestrationStateEntity> orchestrationStateEntitySegment)
{
var stateEntitiesToDelete = new List <OrchestrationStateEntity>(orchestrationStateEntitySegment.Results);
var historyEntitiesToDelete = new ConcurrentBag <IEnumerable <OrchestrationHistoryEventEntity> >();
await Task.WhenAll(orchestrationStateEntitySegment.Results.Select(
entity => Task.Run(async() =>
{
IEnumerable <OrchestrationHistoryEventEntity> historyEntities =
await
tableClient.ReadOrchestrationHistoryEventsAsync(
entity.State.OrchestrationInstance.InstanceId,
entity.State.OrchestrationInstance.ExecutionId).ConfigureAwait(false);
historyEntitiesToDelete.Add(historyEntities);
})));
List <Task> historyDeleteTasks = historyEntitiesToDelete.Select(
historyEventList => tableClient.DeleteEntitesAsync(historyEventList)).Cast <Task>().ToList();
// need to serialize history deletes before the state deletes so we dont leave orphaned history events
await Task.WhenAll(historyDeleteTasks).ConfigureAwait(false);
await Task.WhenAll(tableClient.DeleteEntitesAsync(stateEntitiesToDelete)).ConfigureAwait(false);
}