Imported Upstream version 6.8.0.73

Former-commit-id: d18deab1b47cfd3ad8cba82b3f37d00eec2170af

mcs/class/System/corefx/NetworkStream.cs

@@ -0,0 +1,18 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace System.Net.Sockets
+{
+	partial class NetworkStream
+	{
+		internal Socket InternalSocket {
+			get {
+				Socket chkSocket = _streamSocket;
+				if (_cleanedUp || chkSocket == null)
+					throw new ObjectDisposedException (GetType ().FullName);
+
+				return chkSocket;
+			}
+		}
+	}
+}