use enumerate when iterating to track index and item

Author: philippem

src/new_index/fetch.rs

@@ -84,18 +84,16 @@ fn bitcoind_fetcher(
     Ok(Fetcher::from(
         chan.into_receiver(),
         spawn_thread("bitcoind_fetcher", move || {
-            let mut fetcher_count = 0;
             let mut blocks_fetched = 0;
             let total_blocks_fetched = new_headers.len();
-            for entries in new_headers.chunks(100) {
+            for (fetcher_count, entries) in new_headers.chunks(100).enumerate() {
                 if fetcher_count % 50 == 0 && total_blocks_fetched >= 50 {
                     info!("fetching blocks {}/{} ({:.1}%)",
                         blocks_fetched,
                         total_blocks_fetched,
                         blocks_fetched as f32 / total_blocks_fetched as f32 * 100.0
                     );
                 }
-                fetcher_count += 1;
                 blocks_fetched += entries.len();
 
                 let blockhashes: Vec<BlockHash> = entries.iter().map(|e| *e.hash()).collect();
@@ -186,10 +184,8 @@ fn blkfiles_reader(blk_files: Vec<PathBuf>, xor_key: Option<[u8; 8]>) -> Fetcher
     Fetcher::from(
         chan.into_receiver(),
         spawn_thread("blkfiles_reader", move || {
-            let mut count = 0;
             let blk_files_len = blk_files.len();
-            for path in blk_files {
-                count += 1;
+            for (count, path) in blk_files.iter().enumerate() {
                 info!("block file reading {:}/{:} {:.2}%",
                     count,
                     blk_files_len,