Trait LeafNode 

pub trait LeafNode<S: WorkflowState = State>: Send + Sync {
    // Required method
    fn execute<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 self,
        ctx: &'life1 mut LeafContext<'life2, S>,
    ) -> Pin<Box<dyn Future<Output = Result<(), GraphError>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait,
             'life2: 'async_trait;
}

声明式业务节点 — 只能读 State + emit Mutation。

设计原则：

• 只能读 State（ctx.state() 返回 &S）
• 只能 emit Mutation（ctx.record()）
• 不能 replace_state / clone_state / fork / merge

与 ExecutorOperation 完全不同维度：

• LeafNode = 业务逻辑（Task, Condition, Barrier, LLM, Tool）
• ExecutorOperation = 执行控制（Parallel, Retry, Loop, SubGraph）

泛型参数

• S — 类型化状态（默认 State = HashMap，向后兼容）

Required Methods

fn execute<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, ctx: &'life1 mut LeafContext<'life2, S>, ) -> Pin<Box<dyn Future<Output = Result<(), GraphError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

执行节点逻辑。

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<S: WorkflowState> LeafNode<S> for BarrierNode<S>

BarrierNode 实现 LeafNode（推荐路径 — 只读 state + pause）。

impl<S: WorkflowState> LeafNode<S> for ConditionNode<S>

ConditionNode 实现 LeafNode（推荐路径 — 只读 state + goto）。