Struct Histogram 

pub struct Histogram { /* private fields */ }

Implementations

impl Histogram

pub fn new(labels: Labels) -> Self

pub fn with_sigdigs(labels: Labels, sigdigs: u8) -> Self

Construct with an explicit HDR significant-digits precision. Use this from a call site that already knows the desired precision (e.g. the runner that has already resolved HDR_SIGDIGS_PROP up the component tree).

pub fn with_sigdigs_from(labels: Labels, component: &Component) -> Self

Construct from a component, walking up the tree to find the configured HDR_SIGDIGS_PROP property. Falls back to DEFAULT_HDR_SIGDIGS if no ancestor declares it. SRD 40 §“HDR significant digits — subtree-scoped setting”.

impl Histogram

pub fn record(&self, value: u64)

Record a value (typically nanoseconds).

pub fn total(&self) -> u64

Lifetime (cumulative) observation count — monotonic, unaffected by snapshot() draining. The cadence capture stamps this onto HistogramValue::cumulative_count.

pub fn snapshot(&self) -> HdrHistogram<u64>

Swap out the current histogram and return the delta.

The returned histogram contains all data since the last snapshot() call. The internal histogram is reset.

pub fn peek_snapshot(&self) -> HdrHistogram<u64>

Produce a snapshot by CLONING the current histogram rather than swapping it out. The instrument keeps accumulating against the same state — no reservoir disturbance — so consumers reading “now” values between reporter ticks don’t steal samples from the next delta snapshot.

Cost: one HDR histogram clone (~200 KiB at 3-significant-digit precision over a 1-hour range). Acceptable for occasional calls — not intended for the per-sample hot path.

pub fn labels(&self) -> &Labels