diff --git a/may_rpc_derive/Cargo.toml b/may_rpc_derive/Cargo.toml
index 6d21b6a..7fc869f 100644
--- a/may_rpc_derive/Cargo.toml
+++ b/may_rpc_derive/Cargo.toml
@@ -17,7 +17,7 @@ description = "RPC framework for Rust based on coroutine."
 proc-macro = true
 
 [dependencies]
-heck = "0.4"
+heck = "0.5"
 quote = "1.0"
 proc-macro2 = "1.0"
 syn = { version = "2.0", features = ["full"] }
diff --git a/src/conetty/queued_writer.rs b/src/conetty/queued_writer.rs
index 08a487a..656acd4 100644
--- a/src/conetty/queued_writer.rs
+++ b/src/conetty/queued_writer.rs
@@ -54,7 +54,10 @@ impl<W: Write> QueuedWriter<W> {
         // only allow the first writer perform the write operation
         // other concurrent writers would just push the data
         if self.data_count.fetch_add(1, Ordering::AcqRel) == 0 {
-            // in any cases this should not block since we have only one writer
+            // it's possible that other writer is blocked by the lock
+            // e.g. the `write_all()` is blocked and data_count is 0
+            // and the next writer would try to acquire the lock
+            // this only relax the write lock contention
             let mut writer = self.writer.lock().unwrap();
 
             loop {