Enum CounterDelta 

pub enum CounterDelta {
    FirstSample,
    Advanced {
        delta: u64,
        elapsed: Duration,
        wrapped: bool,
    },
    Reset,
}

What one counter reading means relative to the previous one.

Returned by CounterTracker::observe for callers that need the raw movement — running totals such as NetworkSnapshot::since_launch accumulate deltas rather than rates. Callers that only want a rate use CounterTracker::rate.

Variants

FirstSample

There was no previous reading, so no delta exists yet.

§8.2 and §26: the first sample of delta-based data is warming up, and it is emphatically not zero.

Advanced

A validated, non-negative movement over a measured monotonic interval.

Fields

delta: u64

How far the counter moved forward.

elapsed: Duration

The monotonic interval the movement happened in.

May be Duration::ZERO when two readings share a timestamp. The delta is still valid as a total in that case, but no rate can be derived from it (§8.1).

wrapped: bool

Whether the movement was reconstructed from a known-width wrap.

Exposed so collectors can record a wrap as a health issue instead of silently trusting a reconstructed delta.

Reset

The counter moved backwards in a way no known width explains.

The tracker has already re-baselined on the offending reading, so the next reading produces a valid delta rather than a second reset (§8.2).

Implementations

impl CounterDelta

pub fn rate(self) -> MetricState<Rate>

The rate this delta represents, as a publishable metric state.

pub const fn advanced_by(self) -> Option<u64>

How far the counter moved, if this reading produced a usable movement.

Returns None for the first sample and for a reset, so a caller accumulating a running total cannot add an invalid delta to it.

pub const fn wrapped(self) -> bool

Whether this reading was reconstructed from a known-width wraparound.

Trait Implementations

impl Clone for CounterDelta

fn clone(&self) -> CounterDelta

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CounterDelta

impl Debug for CounterDelta

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

Formats the value using the given formatter.

impl Eq for CounterDelta

impl PartialEq for CounterDelta

fn eq(&self, other: &CounterDelta) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for CounterDelta