db read with mmap

benches/db_bench.rs

@@ -3,7 +3,7 @@ extern crate criterion;
 
 #[path = "../src/db.rs"]
 mod db;
-use std::{path::PathBuf};
+use std::path::PathBuf;
 
 use db::{Reader, Writer, WriterOpts};
 
@@ -88,6 +88,5 @@ fn config() -> Criterion {
     Criterion::default().sample_size(40)
 }
 
-
-criterion_group!{name=benches; config = config(); targets = db_read, db_write}
+criterion_group! {name=benches; config = config(); targets = db_read, db_write}
 criterion_main!(benches);