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

An open *sibling* span row held in `OpentelemetryStatifier.SpanTable`
between a sibling package's `:start` event and the `:stop` whose
`span_ref` matches - today only
`[:statifier_persistence, :execution, :step, :start | :stop]`, the one
start/stop pair the sibling contracts define (sp-ADR-0009's step seam;
`sob-ADR-0006` deliberately has no pairs).

It is a separate row shape from `OpentelemetryStatifier.SpanEntry`
because a sibling span is scoped to a *process*, not to a logical
session: the step seam brackets one serialized drive on the calling
process and knows an `execution_id`, while `session_id` is `nil` until a
position has been decoded. `pid` therefore rides in element 2 of the
row (where the macrostep rows carry `session_id`), which is what lets
the sweep find every sibling row for a dead process with one
`:ets.match_object/2`, and what lets a macrostep span find the step
span open around it in its own process.

`ctx` is the OTel context with this span set as the current one. It is
stored rather than rebuilt so a nested span - the durable macrostep
span, an adapter-call span - starts from exactly this span without
reading or writing the process's ambient context
(`docs/adr/0004-sibling-setup-calls-and-bridge-owned-nesting.md`).

`started_at` orders a process's open sibling spans: a parent execution
creating a durable child inside its own step opens a second step span
on the same process, and the innermost one is the parent of what
follows.

# `t`

```elixir
@type t() :: %OpentelemetryStatifier.SiblingEntry{
  ctx: OpenTelemetry.Ctx.t(),
  span_ctx: OpenTelemetry.span_ctx(),
  started_at: integer()
}
```

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