flat_map_iter is 11% faster than flat_map 0uo

Cargo.lock

@@ -1,7 +1,5 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
-
 [[package]]
 name = "arrayvec"
 version = "0.5.2"

src/files.rs

@@ -150,7 +150,7 @@ pub fn scan_from_walkdir(
 				// split the entries into chunks of 32, and iterate over each chunk of entries in a separate thread
 				return entries
 					.par_chunks(CHUNKS)
-					.flat_map(|chunk| {
+					.flat_map_iter(|chunk| {
 						chunk
 							.iter() // iter over the chunk, which is a slice of DirEntry structs
 							.map(|entry| scan_file(entry, canonical_paths))

src/main.rs

@@ -123,12 +123,16 @@ fn main() {
 	for result in &results {
 		match result {
 			Ok(r) => {
-				debug!(
+				// check to see if debug logging is enabled before invoking debug! macro
-					"{:?} is of type {}, should have extension \"{}\"",
+				// https://github.com/rust-lang/log/pull/394#issuecomment-630490343
-					r.file,
+				if log::max_level() >= log::Level::Debug {
-					r.mime,
+					debug!(
-					r.recommended_extension().unwrap_or_else(|| "???".into())
+						"{:?} is of type {}, should have extension \"{}\"",
-				);
+						r.file,
+						r.mime,
+						r.recommended_extension().unwrap_or_else(|| "???".into())
+					);
+				}
 			}
 			Err(f) => warn!("{}", f),
 		}