Add a quick benchmark

bench/bench.rs

@@ -0,0 +1,34 @@
+#![feature(test, core)]
+
+use bytes::ByteBuf;
+use bytes::traits::*;
+use iobuf::{RWIobuf};
+use test::Bencher;
+
+extern crate bytes;
+extern crate iobuf;
+extern crate test;
+
+const SIZE:usize = 4_096;
+
+#[bench]
+pub fn bench_byte_buf_fill_4kb(b: &mut Bencher) {
+    b.iter(|| {
+        let mut buf = ByteBuf::mut_with_capacity(SIZE);
+
+        for _ in 0..SIZE {
+            buf.write_slice(&[0]);
+        }
+    });
+}
+
+#[bench]
+pub fn bench_rw_iobuf_fill_4kb(b: &mut Bencher) {
+    b.iter(|| {
+        let mut buf = RWIobuf::new(SIZE);
+
+        for _ in 0..SIZE {
+            let _ = buf.fill(&[0]);
+        }
+    });
+}