问从列表中选择每1000项，并将其传递给一个方法

EN

int groupSize = 1000;

//Batch the data
var batches = tracker.Parse()
  .Select((contact, index) => new { contact, index })
  .GroupBy(_ => _.index / groupSize, _ => _.contact);

//Process the batches.
foreach (var batch in batches) {
    //Each batch would be IEnumerable<TContact>
    ProcessBatch(batch);
}

public static void ProcessInBatches<TItem>(this IEnumerble<TItem> items, int batchSize, Action<IEnumerable<TItem>> processBatch) {

    //Batch the data
    var batches = items
      .Select((item, index) => new { item, index })
      .GroupBy(_ => _.index / batchSize, _ => _.item);

    //Process the batches.
    foreach (var batch in batches) {
        //Each batch would be IEnumerable<TItem>
        processBatch(batch);
    }
}