message: add one more explanatory comment
diff: @@ -270,6 +270,10 @@ namespace eosio { namespace chain {
  chainbase::database& get_mutable_database() { return _db; }
  bool should_check_scope()const { return !(_skip_flags&skip_scope_check); }
  +
  + // returns true to indicate that the caller should interpret the current block or transaction
  + // as one that is being produced, or otherwise validated. This is never true if the block is
  + // received as part of catching up with the rest of the chain, and is known to be irreversible.
  bool is_producing()const { return (_skip_flags & (received_block | pushed_transaction)) && !(_skip_flags & irreversible); }
  const deque<signed_transaction>& pending()const { return _pending_transactions; }
  