prevent aggresive optimizations over const_casted buf

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "lightws"
-version = "0.6.11"
+version = "0.6.12"
 authors = ["zephyr <[email protected]>"]
 description = "Lightweight websocket implement for stream transmission."
 repository = "https://github.com/zephyrchien/lightws"

src/lib.rs

@@ -1,6 +1,5 @@
 #![allow(incomplete_features)]
 #![allow(clippy::blocks_in_conditions)]
-#![feature(const_slice_from_raw_parts_mut)]
 #![feature(read_buf)]
 #![feature(core_io_borrowed_buf)]
 #![feature(specialization)]

src/stream/detail/write.rs

@@ -127,9 +127,11 @@ impl<Role: AutoMaskClientRole> WriteFrameHeadTrait<Role> for WriteFrameHead<Role
             role.mask_key().to_key()
         };
 
-        // !! const_cast a immutable reference
         unsafe {
+            // !! const_cast a immutable reference
             let buf = const_cast(buf);
+            // prevent too aggresive optimizations
+            let buf = std::hint::black_box(buf);
             apply_mask4(key, buf);
         }