private static void CopyOverHeader(RecordLocatorResults fileLocs, IMutagenReadStream inputStream, BinaryWriter writer) { long noRecordLength; if (fileLocs.GrupLocations.TryGetInDirection( inputStream.Position, higher: true, result: out var nextRec)) { noRecordLength = nextRec.Value.Location.Min - inputStream.Position; } else { noRecordLength = inputStream.Remaining; } inputStream.WriteTo(writer.BaseStream, (int)noRecordLength); }