fix

Author: stanislav-tkach

rust/cardano-chain-follower/examples/follow_chains.rs

@@ -176,7 +176,7 @@ async fn follow_for(network: Network, matches: ArgMatches) {
     let mut largest_aux_size: usize = 0;
 
     while let Some(chain_update) = follower.next().await {
-        updates += 1;
+        updates = updates.saturating_add(1);
 
         if chain_update.tip {
             reached_tip = true;
@@ -196,7 +196,7 @@ async fn follow_for(network: Network, matches: ArgMatches) {
                 info!(
                     chain = network.to_string(),
                     "Chain Update {}:{}",
-                    updates - 1,
+                    updates.saturating_sub(1),
                     last_update
                 );
             }