InternalDelete method
      
Future<void> 
InternalDelete(
    
- DeleteMode deleteMode,
- SendCancellationsMode? sendCancellationsMode,
- AffectedTaskOccurrence? affectedTaskOccurrences, [
- bool suppressReadReceipts = false,
override
    Implementation
Future<void> InternalDelete(
    DeleteMode deleteMode,
    SendCancellationsMode? sendCancellationsMode,
    AffectedTaskOccurrence? affectedTaskOccurrences,
    [bool suppressReadReceipts = false]) {
  this.ThrowIfThisIsNew();
  this.ThrowIfThisIsAttachment();
  // If sendCancellationsMode is null, use the default value that's appropriate for item type.
  if (sendCancellationsMode == null) {
    sendCancellationsMode = this.DefaultSendCancellationsMode;
  }
  // If affectedTaskOccurrences is null, use the default value that's appropriate for item type.
  if (affectedTaskOccurrences == null) {
    affectedTaskOccurrences = this.DefaultAffectedTaskOccurrences;
  }
  return this.Service.DeleteItem(this.Id, deleteMode, sendCancellationsMode,
      affectedTaskOccurrences, suppressReadReceipts);
}