Glean is a modern approach for recording and sending Telemetry data.
It's in use at Mozilla.
All documentation can be found online:
The different metric types supported by the Glean SDK to handle data.
Ping collection, assembly & submission.
The common set of data shared across all different metric types.
The Glean configuration.
The object holding meta information about a Glean instance.
The possible error types for metric recording. Note: the cases in this enum must be kept in sync with the ones in the platform-specific code (e.g. ErrorType.kt) and with the metrics in the registry files.
The supported metrics' lifetimes.
Get the number of recorded errors for the given metric and error type.