Remove unused fields

internal/nbconn/nbconn.go

@@ -96,11 +96,6 @@ type NetConn struct {
 
 	writeDeadlineLock sync.Mutex
 	writeDeadline     time.Time
-
-	// nbOperCnt Tracks how many operations performing simultaneously
-	nbOperCnt int
-	// nbOperMu Used to prevent concurrent SetBlockingMode calls
-	nbOperMu sync.Mutex
 }
 
 func NewNetConn(conn net.Conn, fakeNonBlockingIO bool) *NetConn {