Macro fail_point 

macro_rules! fail_point {
    ($name:expr) => { ... };
    ($scope:expr, $name:expr) => { ... };
}

Inject a fail point. Does nothing at runtime without the failpoints feature.

Usage in production code: nodedb_types::fail_point!(scope, "calvin_static::during_overlay_stage"); nodedb_types::fail_point!("wal::roll_before_seal"); (no node identity)

Tests opt in by enabling the feature and arming actions: FailGuard::for_node(node_id, "calvin_static::during_overlay_stage", FailAction::Panic);