Attribute Macro handler 

#[handler]

Available on crate feature di only.

Marks a type as part of the Handler layer (Layer 4)

Handlers are entry points (HTTP/gRPC/GraphQL) and can only depend on Use Cases. Handlers CANNOT depend on Repositories directly - they must go through Use Cases.

Example

#[handler]
struct GetUserHandler {
    use_case: Arc<GetUserUseCase>,
}