kern: implement SvcSendSyncRequest(WithUserBuffer)

libraries/libmesosphere/include/mesosphere/kern_k_client_session.hpp

@@ -38,9 +38,11 @@ namespace ams::kern {
 
             static void PostDestroy(uintptr_t arg) { /* ... */ }
 
-            constexpr const KSession *GetParent() const { return this->parent; }
+            constexpr KSession *GetParent() const { return this->parent; }
+
+            Result SendSyncRequest(uintptr_t address, size_t size);
+            Result SendAsyncRequest(KWritableEvent *event, uintptr_t address, size_t size);
 
-            /* TODO: More of KClientSession. */
             void OnServerClosed();
     };