function CopyStream(const AStream: TStream): TMemoryStream;
var
  LBuffer: TBytes;
  LCount: Integer;
begin
  Result := TMemoryStream.Create;
  try
    SetLength(LBuffer, 1024 * 32);
    while True do
    begin
      LCount := AStream.Read(LBuffer, Length(LBuffer));
      Result.Write(LBuffer, LCount);
      if LCount < Length(LBuffer) then
        break;
    end;
  except
    Result.Free;
    raise;
  end;
end;