public KeyValuePair<RecordKey, RecordUpdate> FindPrev(IComparable<RecordKey> keytest, bool equal_ok)
{
FindRecordResult result = _findRecord(keytest, !equal_ok);
if (result.before_keytest.have_record) {
return result.before_keytest.record;
} else {
throw new KeyNotFoundException("SegmentBlockBasic: failed to find match : " + keytest.ToString());
}
}