---
title: Reference
description: Every type, builder method, configuration field, default and error in rtb-telemetry.
---
# Reference
Exact behaviour of the crate's public surface: what each item is, what it
defaults to, and what happens when it is wrong. Prose explanations of *why*
live under [Explanation](../explanation/index.md); task-shaped instructions
live under [How-to](../how-to/index.md).
The generated API listing is on
[docs.rs/rtb-telemetry](https://docs.rs/rtb-telemetry). These pages cover the
things a generated listing cannot: defaults, failure modes, and the parts of
the behaviour that are not visible in a signature.
| [`TelemetryContext` and its builder](telemetry-context.md) | Which builder fields are required, what the defaults are, when `build()` panics, what `record` does when collection is disabled. |
| [`Event` and its JSON shape](event.md) | Field names on the wire, which fields are omitted, timestamp format, severity mapping. |
| [Sinks](sinks.md) | The five built-in sinks, every configuration field with its default, and what each one does on failure. |
| [The consent file](consent-file.md) | On-disk TOML format, the schema version rule, and the three functions that read, write and delete it. |
| [Cargo features](cargo-features.md) | What `remote-sinks` turns on, what is enabled by default, the MSRV, and the runtime the crate needs. |
| [Errors](errors.md) | Every `TelemetryError` variant, its message, its diagnostic code, and which call produces it. |
## Version this documents
These pages were written against **rtb-telemetry 0.7.3**. Where behaviour is
version-sensitive — the OTLP transports especially — the page says which
version was tested.