Split out 'socket' hosting model into a separate optional NuGet package, since most developers won't need it

src/Microsoft.AspNetCore.NodeServices.Sockets/PhysicalConnections/NamedPipeConnection.cs

@@ -0,0 +1,44 @@
+using System.IO;
+using System.IO.Pipes;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.NodeServices.Sockets.PhysicalConnections
+{
+    internal class NamedPipeConnection : StreamConnection
+    {
+        private bool _disposedValue = false;
+        private NamedPipeClientStream _namedPipeClientStream;
+
+#pragma warning disable 1998 // Because in the NET451 code path, there's nothing to await
+        public override async Task<Stream> Open(string address)
+        {
+            _namedPipeClientStream = new NamedPipeClientStream(
+                ".",
+                address,
+                PipeDirection.InOut,
+                PipeOptions.Asynchronous);
+
+#if NET451
+            _namedPipeClientStream.Connect();
+#else
+            await _namedPipeClientStream.ConnectAsync().ConfigureAwait(false);
+#endif
+
+            return _namedPipeClientStream;
+        }
+#pragma warning restore 1998
+
+        public override void Dispose()
+        {
+            if (!_disposedValue)
+            {
+                if (_namedPipeClientStream != null)
+                {
+                    _namedPipeClientStream.Dispose();
+                }
+
+                _disposedValue = true;
+            }
+        }
+    }
+}