It Was a Bug. It Fixed here.
The issue was 4415
I changed res.send(buffer.slice(0, req.query.size)) by res.send(buffer.slice(0, req.query.size).toString()) as a workaround for this test.
res.send(buffer.slice(0, req.query.size))
res.send(buffer.slice(0, req.query.size).toString())