No-op audit forwarder.
Warning
This forwarder silently drops all audit events — no audit forwarding
happens when it is attached. It is provided for explicit use in test
environments or when you want to satisfy the Sigra.Audit.Forwarder
behaviour contract without wiring a real backend.
Degraded-dep behaviour (D-22, D-23)
When a configured forwarder module (e.g. Sigra.Audit.Forwarders.Threadline)
is not loaded at boot time, Sigra.Application.attach_forwarders/0
skips the attach call entirely — it does NOT substitute Noop. A
Logger.warning is emitted by
Sigra.Application.maybe_warn_missing_forwarder_deps/0 to alert
operators, but zero forwarding happens (silent degrade, not Noop degrade).
Noop is only active when it is explicitly listed in your
sigra_config/0 audit: [forwarders: []] block. To enable real
forwarding, add the corresponding dep (e.g.
{:threadline, "~> 0.5", optional: true}) to mix.exs, or remove
the forwarder entry from the config block.
This module does NOT subscribe to telemetry and does NOT emit log
output. attach/1 returns :ok immediately (D-22).