Contract for host-owned instrumentation backends.
execute/3 is required. Handler management is optional; implement
attach_many/4 and detach/1 to support the corresponding helpers in
ExWapp.Telemetry. The Erlang :telemetry module already has this interface.
Summary
Callbacks
@callback attach_many(term(), [[atom()]], ExWapp.Telemetry.handler(), term()) :: :ok | {:error, term()}