I thought Dafny has access to the .NET infrastructure. But when I played with Dafny a while back, the only library interface I saw was printing to stdout (IIRC)

I thought Dafny has access to the .NET infrastructure. But when I played with Dafny a while back, the only library interface I saw was printing to stdout (IIRC), which would imply that Dafny was a toy language intended for playing with verification and not much else. On the other hand, I've heard otherwise---it's been used for Windows drivers?---but without any documentation or examples, I lost interest.