diff --git a/transport/http2_client.go b/transport/http2_client.go
index 1420b1668..00a167209 100644
--- a/transport/http2_client.go
+++ b/transport/http2_client.go
@@ -79,6 +79,7 @@ type http2Client struct {
 	fc         *inFlow
 	// sendQuotaPool provides flow control to outbound message.
 	sendQuotaPool *quotaPool
+	// streamsQuota limits the max number of concurrent streams.
 	streamsQuota  *quotaPool
 
 	// The scheme used: https if TLS is on, http otherwise.
@@ -248,6 +249,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 			t.mu.Unlock()
 			return nil, err
 		}
+		// Returns the quota balance back.
 		if q > 1 {
 			t.streamsQuota.add(q-1)
 		}
diff --git a/transport/transport.go b/transport/transport.go
index 052f2618e..5dfd89f0d 100644
--- a/transport/transport.go
+++ b/transport/transport.go
@@ -451,14 +451,3 @@ func wait(ctx context.Context, closing <-chan struct{}, proceed <-chan int) (int
 		return i, nil
 	}
 }
-
-func wait64(ctx context.Context, closing <-chan struct{}, proceed <-chan int64) (int64, error) {
-	select {
-	case <-ctx.Done():
-		return 0, ContextErr(ctx.Err())
-	case <-closing:
-		return 0, ErrConnClosing
-	case i := <-proceed:
-		return i, nil
-	}
-}