flag a bunch of method functions as deprecated

Summary: None of these should exist in the public API, but we are out of time before MVP so just deprecating

Differential Revision: D49747135

Author: JacobSzwejbka

runtime/executor/method.h

@@ -196,17 +196,25 @@ class Method final {
    */
   __ET_NODISCARD Error experimental_reset_execution();
 
-  size_t values_size() const;
-  const EValue& get_value(size_t i) const;
-  EValue& mutable_value(size_t i);
+  __ET_DEPRECATED size_t values_size() const;
+  __ET_DEPRECATED const EValue& get_value(size_t i) const;
+  __ET_DEPRECATED EValue& mutable_value(size_t i);
   size_t inputs_size() const;
-  size_t get_input_index(size_t i) const;
-  const EValue& get_input(size_t i) const;
-  EValue& mutable_input(size_t i);
+  /// DEPRECATED: Use MethodMeta instead to access metadata, and set_input to
+  /// update Method inputs.
+  __ET_DEPRECATED size_t get_input_index(size_t i) const;
+  /// DEPRECATED: Use MethodMeta instead to access metadata, and set_input to
+  /// update Method inputs.
+  __ET_DEPRECATED const EValue& get_input(size_t i) const;
+  /// DEPRECATED: Use MethodMeta instead to access metadata, and set_input to
+  /// update Method inputs.
+  __ET_DEPRECATED EValue& mutable_input(size_t i);
   size_t outputs_size() const;
-  size_t get_output_index(size_t i) const;
+  __ET_DEPRECATED size_t get_output_index(size_t i) const;
   const EValue& get_output(size_t i) const;
-  EValue& mutable_output(size_t i);
+  /// DEPRECATED: Use MethodMeta instead to access metadata, and get_output to
+  /// retrieve Method outputs.
+  __ET_DEPRECATED EValue& mutable_output(size_t i);
   ~Method();
 
  private: