message: add smartconstructor for StatePtr
diff: @@ -44,6 +44,11 @@ pub struct StatePtr {
  latest_addr: BlockDate,
  latest_known_hash: HeaderHash,
  }
  +impl StatePtr {
  + pub fn new(latest_addr: BlockDate, latest_known_hash: HeaderHash) -> Self {
  + StatePtr { latest_addr, latest_known_hash }
  + }
  +}
  #[derive(Clone,Debug)]
  pub struct State<T: AddrLookup> {
  