# `BB.Dsl.Estimator.Input`
[🔗](https://github.com/beam-bots/bb/blob/main/lib/bb/dsl/estimator/input.ex#L5)

A declared input on a cross-sensor estimator.

Inputs are only used by link-nested estimators. Sensor-nested estimators
consume their parent sensor's output implicitly.

Exactly one input on a multi-input estimator must be marked `driver?:
true`. The driver's arrival triggers fan-in: the framework snapshots the
most-recent non-driver input messages and dispatches them together. If
any non-driver input is stale relative to the driver by more than the
estimator's `sync_tolerance`, the dispatch is dropped.

Single-input link-nested estimators omit `driver?:` (or set it to `true`
on the sole input).

# `t`

```elixir
@type t() :: %BB.Dsl.Estimator.Input{
  __identifier__: any(),
  __spark_metadata__: Spark.Dsl.Entity.spark_meta(),
  driver?: boolean(),
  name: atom(),
  path: [atom()]
}
```

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