+/** Sets the key method data of an EC_KEY object, if none has yet been set.
+ * \param key EC_KEY object
+ * \param data opaque data to install.
+ * \param dup_func a function that duplicates |data|.
+ * \param free_func a function that frees |data|.
+ * \param clear_free_func a function that wipes and frees |data|.
+ * \return the previously set data pointer, or NULL if |data| was inserted.
+ */
+void *EC_KEY_insert_key_method_data(EC_KEY *key, void *data,