Function tracing_callback 

pub fn tracing_callback() -> MessageCallback

Create a MessageCallback that emits structured tracing events for every message variant.

Variant	Level	Fields
System	INFO	session_id
Assistant	DEBUG	(message variant only)
User	DEBUG	(message variant only)
Result	INFO	stop_reason, is_error
StreamEvent	TRACE	event_type

Example

use gemini_cli_sdk::callback::tracing_callback;

let cb = tracing_callback();
// Pass `cb` to `ClientConfig::builder().on_message(cb).build()`.