如何在Delphi中为保存的文件增加数量？

var
  FileStream: TFileStream;
  Data: TBytes;
begin
  FileStream := TFileStream.Create('file.txt', fmCreate or fmShareDenyWrite);
  try
    Data := TEncoding.UTF8.GetBytes('Hello, world!');
    FileStream.Write(Data, Length(Data));
  finally
    FileStream.Free;
  end;
end;

begin
  TFile.WriteAllText('file.txt', 'Hello, world!');
  // 或
  TFile.WriteAllBytes('file.bin', TEncoding.UTF8.GetBytes('Hello, world!'));
end;

var
  StreamWriter: TStreamWriter;
begin
  StreamWriter := TStreamWriter.Create('file.txt');
  try
    StreamWriter.WriteLine('Hello, world!');
  finally
    StreamWriter.Free;
  end;
end;

var
  StringList: TStringList;
begin
  StringList := TStringList.Create;
  try
    StringList.Add('Hello, world!');
    StringList.SaveToFile('file.txt');
  finally
    StringList.Free;
  end;
end;