Macro node 

macro_rules! node {
    (|$state:ident| async move $body:block) => { ... };
    ($name:expr, |$state:ident| async move $body:block) => { ... };
    (|$state:ident, $config:ident| async move $body:block) => { ... };
    ($name:expr, |$state:ident, $config:ident| async move $body:block) => { ... };
}

Helper macro to create a node from an async closure.

Forms

// Basic form (backward compatible) - body returns Result<()>
node!(|state| async move {
    state.set("key", "value").await?;
    Ok(())
})

// Named form - body returns Result<()>
node!("my_node", |state| async move {
    state.set("key", "value").await?;
    Ok(())
})

// With config - body returns Result<NodeOutput> or Result<()>
node!(|state, config| async move {
    state.set("key", "value").await?;
    Ok(NodeOutput::Done)
})

// Named with config
node!("my_node", |state, config| async move {
    state.set("key", "value").await?;
    Ok(())
})