How to look into StreamSocket for data in UWP apps

With the Socket class, I can use the Socket.ReceiveAsync method by passing in the SocketFlags.Peek flag. However, I don't see anything like this for StreamSocket.

The UWP InputStreamOptions enum provides Partial and ReadAhead flags, but from their description it doesn't seem like they serve the same purpose (checking data availability, leaving data in the input buffer).