Type Alias BeforeModelCallback 

pub type BeforeModelCallback = Box<dyn Fn(Arc<dyn CallbackContext>, LlmRequest) -> Pin<Box<dyn Future<Output = Result<BeforeModelResult, AdkError>> + Send>> + Sync + Send>;

Core traits and types.

Always available regardless of feature flags. Includes:

• Agent - The fundamental trait for all agents
• Tool / Toolset - For extending agents with capabilities
• Session / State - For managing conversation context
• Event - For streaming agent responses
• AdkError / Result - Unified error handling

Aliased Type

pub struct BeforeModelCallback(/* private fields */);