function ReadStreamStr(Stream: TStream): string;
var
  StringStream: TStringStream;
begin
  Result := '';
  StringStream := TStringStream.Create;
  try
    StringStream.LoadFromStream(Stream);
    Result := StringStream.DataString;
  finally
    StringStream.Free;
  end;
end;

procedure WriteStreamStr(Stream: TStream; const Str: string);
var
  StringStream: TStringStream;
begin
  StringStream := TStringStream.Create(Str);
  try
    Stream.CopyFrom(StringStream, 0);
  finally
    StringStream.Free;
  end;
end;