Fix test

internal/multiplex/datagramBuffer_test.go

@@ -2,7 +2,6 @@ package multiplex
 
 import (
 	"bytes"
-	"sync/atomic"
 	"testing"
 	"time"
 )
@@ -67,7 +66,7 @@ func TestDatagramBuffer_RW(t *testing.T) {
 			)
 			return
 		}
-		if atomic.LoadUint32(&pipe.closed) != 1 {
+		if !pipe.closed {
 			t.Error("expecting closed pipe, not closed")
 		}
 	})