Struct BuildTimeoutSetEvent 

pub struct BuildTimeoutSetEvent {
    pub set_type: TimeoutSetType,
    pub total_times: Option<u32>,
    pub timeout: Option<u32>,
    pub xm: Option<u32>,
    pub alpha: Option<f64>,
    pub quantile: Option<f64>,
    pub timeout_rate: Option<f64>,
    pub close_timeout: Option<u32>,
    pub close_rate: Option<f64>,
    /* private fields */
}

Event indicating that the circuit build timeout has changed.

Tor dynamically adjusts its circuit build timeout based on observed circuit construction times. This event is emitted when the timeout value changes, providing insight into network performance.

Timeout Calculation

Tor uses a Pareto distribution to model circuit build times:

• xm - The Pareto Xm parameter (minimum value)
• alpha - The Pareto alpha parameter (shape)
• quantile - The CDF cutoff quantile

Set Types

The set_type indicates why the timeout changed:

• TimeoutSetType::Computed - Calculated from observed times
• TimeoutSetType::Reset - Reset to default values
• TimeoutSetType::Suspended - Timeout learning suspended
• TimeoutSetType::Discard - Discarding learned values
• TimeoutSetType::Resume - Resuming timeout learning

Example

use stem_rs::events::BuildTimeoutSetEvent;

fn handle_timeout(event: &BuildTimeoutSetEvent) {
    if let Some(timeout) = event.timeout {
        println!("Circuit timeout set to {}ms ({:?})", timeout, event.set_type);
    }
    if let Some(rate) = event.timeout_rate {
        println!("Timeout rate: {:.2}%", rate * 100.0);
    }
}

See Also

• TimeoutSetType - Timeout change reasons

Fields

set_type: TimeoutSetType

Type of timeout change.

total_times: Option<u32>

Number of circuit build times used to calculate timeout.

timeout: Option<u32>

Circuit build timeout in milliseconds.

xm: Option<u32>

Pareto Xm parameter in milliseconds.

alpha: Option<f64>

Pareto alpha parameter.

quantile: Option<f64>

CDF quantile cutoff point.

timeout_rate: Option<f64>

Ratio of circuits that timed out.

close_timeout: Option<u32>

Duration to keep measurement circuits in milliseconds.

close_rate: Option<f64>

Ratio of measurement circuits that were closed.

Implementations

impl BuildTimeoutSetEvent

pub fn parse(content: &str) -> Result<Self, Error>

Parses a build timeout set event from raw control protocol content.

Arguments

• content - The event content after the event type

Event Format

SetType [TOTAL_TIMES=...] [TIMEOUT_MS=...] [XM=...] [ALPHA=...]
[CUTOFF_QUANTILE=...] [TIMEOUT_RATE=...] [CLOSE_MS=...] [CLOSE_RATE=...]

Errors

Returns Error::Protocol if:

• The set type is missing or unrecognized
• Numeric values cannot be parsed

Trait Implementations

impl Clone for BuildTimeoutSetEvent

fn clone(&self) -> BuildTimeoutSetEvent

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BuildTimeoutSetEvent

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

Formats the value using the given formatter.

impl Event for BuildTimeoutSetEvent

fn event_type(&self) -> EventType

Returns the type of this event.

fn raw_content(&self) -> &str

Returns the raw, unparsed content of the event.

fn arrived_at(&self) -> Instant

Returns the instant when this event was received.