Enum LiveEvent 

#[non_exhaustive]
pub enum LiveEvent {
    Audio(Bytes),
    Media(InlineMedia),
    TextDelta(String),
    TextComplete(String),
    InputTranscript {
        text: String,
        is_final: bool,
    },
    OutputTranscript {
        text: String,
        is_final: bool,
    },
    Thought(String),
    VadStart,
    VadEnd,
    TasksChanged(TaskSessionSnapshot),
    Extraction {
        name: String,
        value: Value,
    },
    ExtractionError {
        name: String,
        error: String,
    },
    StatePromotion {
        extractor: String,
        field: String,
        state_key: String,
        accepted: bool,
        reason: String,
        value: Value,
    },
    PhaseTransition {
        from: String,
        to: String,
        reason: String,
    },
    ToolExecution {
        name: String,
        args: Value,
        result: Value,
    },
    ToolCancelled {
        ids: Vec<String>,
    },
    TurnComplete,
    Interrupted,
    FillerCue {
        tool: String,
        elapsed_ms: u64,
    },
    VerbatimChecked {
        step: String,
        similarity: f64,
        passed: bool,
    },
    Reprompted {
        silence_ms: u64,
    },
    Connected,
    Disconnected {
        reason: Option<String>,
    },
    Error(String),
    GoAway {
        time_left: Duration,
    },
    Telemetry(Value),
    TurnMetrics {
        turn: u32,
        latency_ms: u32,
        prompt_tokens: u32,
        response_tokens: u32,
    },
}

Semantic events emitted by the Live session processor.

The L1 equivalent of L0’s SessionEvent. L0 events are wire-level; LiveEvents are semantic (extractions completed, phases transitioned, tools executed).

Subscribe via LiveHandle::events(). Multiple independent subscribers supported. Sending with no subscribers is a no-op (broadcast::send with 0 receivers stores nothing); the buffer itself is allocated when the session starts, sized by LiveSessionBuilder::event_capacity.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Audio(Bytes)

Raw PCM audio from model. Uses Bytes (refcounted) — clone is a pointer increment (~2ns), not a deep copy.

Media(InlineMedia)

Non-audio media from the model: Gemini 3.8 Live Avatar video (video/mp4), synchronized with Audio.

TextDelta(String)

Incremental text token from model.

TextComplete(String)

Complete text response (all deltas concatenated).

InputTranscript

User speech transcription.

Fields

text: String

The transcribed text content.

is_final: bool

Whether this is the final transcription for the utterance.

OutputTranscript

Model speech transcription.

Fields

text: String

The transcribed text content.

is_final: bool

Whether this is the final transcription for the utterance.

Thought(String)

Model reasoning/thinking content.

VadStart

Voice activity detected — user started speaking.

VadEnd

Voice activity ended — user stopped speaking.

TasksChanged(TaskSessionSnapshot)

A task lifecycle, approval, operation, or foreground changed.

Extraction

Extraction completed. Emitted for both the top-level result AND each flattened key (e.g., “order.items”, “order.phase”).

Fields

name: String

Extractor name, or "extractor.field" for flattened keys.

value: Value

The extracted JSON value.

ExtractionError

Extraction failed.

Fields

name: String

Name of the extractor that failed.

error: String

Human-readable error description.

StatePromotion

A raw extraction field was considered for promotion into authoritative state.

Fields

extractor: String

Extractor name that produced the field.

field: String

Field name inside the extractor result.

state_key: String

State key targeted by the promotion rule.

accepted: bool

Whether the promotion was accepted and written.

reason: String

Human-readable reason for the decision.

value: Value

Extracted value that was considered.

PhaseTransition

Phase machine transitioned.

Fields

from: String

Phase the machine transitioned from.

to: String

Phase the machine transitioned to.

reason: String

Human-readable reason for the transition.

ToolExecution

Tool dispatched and result obtained.

Fields

name: String

Name of the tool that was called.

args: Value

Arguments passed to the tool.

result: Value

Result returned by the tool.

ToolCancelled

Tool calls cancelled — either by the server (a ToolCallCancelled wire event) or locally when a user barge-in interrupted an in-flight inline tool. No response is sent for a cancelled call, and a cancelled call never advances the governed flow.

Fields

ids: Vec<String>

IDs of the cancelled tool calls.

TurnComplete

Model completed a conversational turn.

Interrupted

Model output interrupted by user speech.

FillerCue

A tool call in a stage with a filler timing has run longer than the stage allows: play an earcon or a holding line now.

Fields

tool: String

The tool still running.

elapsed_ms: u64

How long it has run, in milliseconds.

VerbatimChecked

A verbatim stage’s required text was compared with what the model said this turn.

Fields

step: String

The stage.

similarity: f64

Word-level similarity, 0–1.

passed: bool

Whether it was close enough to count as verbatim.

Reprompted

The user stayed silent past the active stage’s reprompt timing, and the model was asked to repeat its question.

Fields

silence_ms: u64

How long the user had been silent, in milliseconds.

Connected

Session connected to Gemini.

Disconnected

Session disconnected.

Fields

reason: Option<String>

Optional reason for disconnection (server-provided or error message).

Error(String)

Unrecoverable error.

GoAway

Server requesting session wind-down.

Fields

time_left: Duration

Time remaining before the server closes the connection.

Telemetry(Value)

Aggregated session telemetry snapshot.

TurnMetrics

Per-turn latency and token metrics.

Fields

turn: u32

Turn number (1-indexed).

latency_ms: u32

End-to-end latency for this turn in milliseconds.

prompt_tokens: u32

Number of prompt tokens consumed.

response_tokens: u32

Number of response tokens generated.

Trait Implementations

impl Clone for LiveEvent

fn clone(&self) -> LiveEvent

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LiveEvent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.