[#1] Define SDK structure

TODO: Вынести маппинг модель -> grpc в отдельный слой

Signed-off-by: Ivan Pchelintsev <i.pchelintsev@yadro.com>

sdk/src/FrostFS.SDK.ProtosV2/session/Extension.Message.cs

@@ -0,0 +1,60 @@
+using Google.Protobuf;
+
+namespace FrostFS.Session
+{
+    public partial class CreateResponse : IResponse
+    {
+        IMetaHeader IVerificableMessage.GetMetaHeader()
+        {
+            return MetaHeader;
+        }
+
+        IVerificationHeader IVerificableMessage.GetVerificationHeader()
+        {
+            return VerifyHeader;
+        }
+
+        void IVerificableMessage.SetMetaHeader(IMetaHeader metaHeader)
+        {
+            MetaHeader = (ResponseMetaHeader)metaHeader;
+        }
+
+        void IVerificableMessage.SetVerificationHeader(IVerificationHeader verificationHeader)
+        {
+            VerifyHeader = (ResponseVerificationHeader)verificationHeader;
+        }
+
+        public IMessage GetBody()
+        {
+            return Body;
+        }
+    }
+
+    public partial class CreateRequest : IRequest
+    {
+        IMetaHeader IVerificableMessage.GetMetaHeader()
+        {
+            return MetaHeader;
+        }
+
+        IVerificationHeader IVerificableMessage.GetVerificationHeader()
+        {
+            return VerifyHeader;
+        }
+
+        void IVerificableMessage.SetMetaHeader(IMetaHeader metaHeader)
+        {
+            MetaHeader = (RequestMetaHeader)metaHeader;
+        }
+
+        void IVerificableMessage.SetVerificationHeader(IVerificationHeader verificationHeader)
+        {
+            VerifyHeader = (RequestVerificationHeader)verificationHeader;
+        }
+
+        public IMessage GetBody()
+        {
+            return Body;
+        }
+    }
+}