为什么Tstringlist.LoadFromfile不能加载一个大小合理的文件？

var
  FileStream: TFileStream;
  StreamReader: TStreamReader;
  Line: string;
begin
  FileStream := TFileStream.Create('文件路径', fmOpenRead);
  StreamReader := TStreamReader.Create(FileStream);
  
  while not StreamReader.EndOfStream do
  begin
    Line := StreamReader.ReadLine;
    // 处理每一行的内容
  end;
  
  StreamReader.Free;
  FileStream.Free;
end;

var
  FileStream: TFileStream;
  Buffer: array of Byte;
  ChunkSize: Integer;
  BytesRead: Integer;
begin
  FileStream := TFileStream.Create('文件路径', fmOpenRead);
  ChunkSize := 1024; // 每次加载的块大小
  
  SetLength(Buffer, ChunkSize);
  
  repeat
    BytesRead := FileStream.Read(Buffer[0], ChunkSize);
    // 处理读取的数据
    
  until BytesRead < ChunkSize;
  
  FileStream.Free;
end;