Module callbacks 

Typed callback registry for Live session events.

Fast lane callbacks (sync, < 1ms): audio, text, transcripts, VAD. Control lane callbacks (async, can block): tool calls, lifecycle, interruptions. Outbound interceptors: transform tool responses, inject context at turn boundaries.

Callback Modes

Each control-lane callback has an associated CallbackMode:

• Blocking — awaited inline. The event loop waits for completion before processing the next event. Guarantees ordering and state consistency.
• Concurrent — spawned as a detached tokio task. The event loop continues immediately. Use for fire-and-forget work (logging, background agent dispatch, analytics).

Fast-lane callbacks (audio, text, VAD) are always sync and inline. Interceptors (before_tool_response, on_turn_boundary) are always blocking.

Some control-lane callbacks are forced-blocking (no concurrent variant): on_interrupted (must clear state before audio resumes), on_tool_call (return value is the tool response).

Structs

EventCallbacks

Typed callback registry for Live session events.

Enums

CallbackMode

Controls how a control-lane callback is executed relative to the event loop.

Type Aliases

AsyncCallback

Control-lane async callback with no payload.

AsyncCallbackWith

Control-lane async callback over one payload value.

AsyncCallbackWith2

Control-lane async callback over two payload values.

AudioCallback

Fast-lane sync callback over a raw audio chunk.

BeforeToolResponseCallback

Middleware over outgoing tool responses (inspect/rewrite before send).

InstructionFn

Sync state-reactive instruction generator (None = leave unchanged).

PhaseCallback

Fast-lane sync callback over a session phase change.

SignalCallback

Fast-lane sync callback with no payload (VAD start/end).

TextCallback

Fast-lane sync callback over a text payload (delta, accumulated text, thought).

ToolCallCallback

Tool-call override: return Some(responses) to reply, None to defer to auto-dispatch via the registered ToolDispatcher.

TranscriptCallback

Fast-lane sync callback over a transcript chunk with its is_final flag.

UsageCallback

Fast-lane sync callback over usage metadata.