Function add_native 

pub fn add_native<H: IntoNativeHandler>(name: &str, handler: H) -> Result<bool>

挂载一个 native 处理函数到 ROOT 树。

第二个参数既可以是内建名(&str,如 “fight”),也可以是任意 Fn(Dynamic) -> Dynamic + Send + Sync 闭包(可带捕获环境)。

注意:示例为说明用途,需在已初始化 ROOT 树的上下文中调用。

// 按名挂内建
let _ = root::add_native("local/fight", "fight");
// 挂顶层 fn
fn h(msg: Dynamic) -> Dynamic { Dynamic::Null }
let _ = root::add_native("local/h", h);
// 挂带捕获的闭包
let state = 42i64;
let closure = move |msg: Dynamic| -> Dynamic { Dynamic::from(state) };
let _ = root::add_native("local/h2", closure);