update comments

src/ngraph/runtime/executable.hpp

@@ -52,6 +52,12 @@ public:
     bool call_with_validate(const std::vector<std::shared_ptr<runtime::Tensor>>& outputs,
                             const std::vector<std::shared_ptr<runtime::Tensor>>& inputs);
 
+    /// \brief Asynchronously executes a single iteration of the Function. The `future` is used
+    ///     to monitor the execution.
+    /// \param outputs vector of runtime::Tensor used as outputs
+    /// \param inputs vector of runtime::Tensor used as inputs
+    /// \returns a valid std::future to monitor the execution. Use future.get() to get the results
+    ///     or future.wait*() to wait for completion.
     virtual std::future<bool>&
         begin_execute(const std::vector<std::shared_ptr<runtime::Tensor>>& outputs,
                       const std::vector<std::shared_ptr<runtime::Tensor>>& inputs);