Returns a specification to start this module under a supervisor.

See Supervisor.

@spec with_span(
  :telemetry.event_prefix(),
  :telemetry.event_metadata(),
  (:telemetry.event_metadata() -> {any(), :telemetry.event_metadata()})
  | (-> any())
) :: any()

Convenience function that wraps :telemetry.span/3.

Given a function with an arity of zero, it passes the metadata argument out with the result of the function.

If you need to control the metadata, pass in a function with an arity of one. It will be called with the metadata provided and expects the result and the updated metadata to be returned in a tuple.

Example:

with_span([:my, span], %{project_id: 123}, fn -> get_project(456) end)

Or when you want to extend the metadata:

with_span([:my, :span], %{user_id: 123}, fn _metadata ->
  project = get_project(456)
  {project, %{project_id: project.id}}
end)