# `OpentelemetryStatifier.SpanEntry`
[🔗](https://github.com/riddler/opentelemetry_statifier/blob/v0.10.0/lib/opentelemetry_statifier/span_entry.ex#L1)

An open macrostep span row held in `OpentelemetryStatifier.SpanTable`
between the macrostep `:start` event that creates it and the `:stop`
event whose `span_ref` matches.

`started_at` is the `monotonic_time` the span was opened with -
`SpanTable.fetch_innermost_open_span/2` orders a session's open spans
by it, and recomputing it from the span ctx is not possible through
the API. (The sweep turned out not to need an age: it keys on session
process liveness, via the table's `:session_pid` rows.)

`macrostep` is the macrostep counter this span covers, and it is the
one field here that is not known when the row is written. Statifier's
`[:statifier, :session, :macrostep, :start]` event carries no
`macrostep` measurement - the counter is authoritative only on the
`:stop` half - so the field starts as `nil` and is filled in by
`OpentelemetryStatifier.Handler` from the first intra-macrostep event
that lands on the span, every one of which carries `macrostep` as a
measurement (st-ADR-0040's event table). It exists so
`OpentelemetryStatifier.SpanContext.lookup/2` can answer a keyed
`(session_id, macrostep)` read; nothing in the span topology depends
on it, and a span nobody ever emitted an effect or trace event inside
keeps `nil` for its whole life.

# `t`

```elixir
@type t() :: %OpentelemetryStatifier.SpanEntry{
  macrostep: non_neg_integer() | nil,
  session_id: String.t(),
  span_ctx: OpenTelemetry.span_ctx(),
  started_at: integer(),
  trigger: atom()
}
```

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*Consult [api-reference.md](api-reference.md) for complete listing*