@@ -118,7 +118,7 @@ func (o *Output) Close() error {

 	defer o.Unlock()

 	var firstErr error

 	for _, dst := range o.dests {

-		if closer, ok := dst.(io.WriteCloser); ok {

+		if closer, ok := dst.(io.Closer); ok {

 			err := closer.Close()

 			if err != nil && firstErr == nil {

 				firstErr = err

@@ -154,7 +154,7 @@ func (i *Input) Read(p []byte) (n int, err error) {

 // Not thread safe on purpose

 func (i *Input) Close() error {

 	if i.src != nil {

-		if closer, ok := i.src.(io.WriteCloser); ok {

+		if closer, ok := i.src.(io.Closer); ok {

 			return closer.Close()

 		}

 	}