message: Log an error when state is missing expected unit.
diff: @@ -2,6 +2,7 @@ use std::fmt::Debug;
  use datasize::DataSize;
  use serde::{Deserialize, Serialize};
  +use tracing::error;
  use crate::components::consensus::{
  highway_core::{
  @@ -42,11 +43,13 @@ impl IndexPanorama {
  for (vid, obs) in panorama.enumerate() {
  let index_obs = match obs {
  Observation::None => IndexObservation::None,
  - Observation::Correct(hash) => state
  - .maybe_unit(hash)
  - .map_or(IndexObservation::None, |unit| {
  - IndexObservation::Correct(unit.seq_number)
  - }),
  + Observation::Correct(hash) => state.maybe_unit(hash).map_or_else(
  + || {
  + error!(?hash, "expected unit to exist in the local protocol state");
  + IndexObservation::None
  + },
  + |unit| IndexObservation::Correct(unit.seq_number),
  + ),
  Observation::Faulty => IndexObservation::Faulty,
  };
  validator_map[vid] = index_obs;
  