Struct Session 

pub struct Session<S: SessionState> {
    data: SessionRecord,
    _state: PhantomData<S>,
}

A stateful LLM session with compile-time state tracking.

The type parameter S indicates the current state of the session. Methods are only available in appropriate states:

• Session<Created>: Can be activated
• Session<Active>: Can record deltas, close, or expire
• Session<Closed>: Terminal, no further transitions
• Session<SessionExpired>: Terminal, no further transitions

Fields

data: SessionRecord

_state: PhantomData<S>

Implementations

impl<S: SessionState> Session<S>

pub fn data(&self) -> &SessionRecord

Access the underlying session data (read-only).

pub fn session_id(&self) -> SessionId

Get the session ID.

pub fn tenant_id(&self) -> TenantId

Get the tenant ID.

pub fn provider_id(&self) -> &str

Get the provider ID.

pub fn model(&self) -> &str

Get the model.

pub fn created_at(&self) -> Timestamp

Get when the session was created.

pub fn round_count(&self) -> u64

Get the round count.

pub fn into_data(self) -> SessionRecord

Consume and return the underlying data (for serialization).

impl Session<Created>

pub fn new(data: SessionRecord) -> Self

Create a new session in the Created state.

pub fn activate(self, activated_at: Timestamp) -> Session<Active>

Activate the session.

Transitions to Session<Active>. Consumes the current session.

impl Session<Active>

pub fn activated_at(&self) -> Timestamp

Get when the session was activated.

pub fn record_delta(&mut self, delta_tokens: u64)

Record a delta (new messages sent to the provider).

This is a looping state — it does not consume self. Increments round_count and accumulates delta_tokens.

pub fn tokens_saved(&self) -> u64

Calculate total tokens saved by using stateful sessions.

Without sessions, each round would re-send the full initial context. Savings = (round_count * initial_tokens) - delta_tokens

pub fn close(self, closed_at: Timestamp) -> Session<Closed>

Close the session normally.

Transitions to Session<Closed> (terminal state). Consumes the current session.

pub fn expire(self, expired_at: Timestamp) -> Session<SessionExpired>

Expire the session due to TTL.

Transitions to Session<SessionExpired> (terminal state). Consumes the current session.

impl Session<Closed>

pub fn closed_at(&self) -> Timestamp

Get when the session was closed.

impl Session<SessionExpired>

pub fn expired_at(&self) -> Timestamp

Get when the session expired.

Trait Implementations

impl<S: Clone + SessionState> Clone for Session<S>

fn clone(&self) -> Session<S>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<S: Debug + SessionState> Debug for Session<S>

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

Formats the value using the given formatter.