How to gracefully end reading bufio.Scaner()?

Question

go

There is a client and a server. The client sends JSON like this:

writer := bufio.NewWriter(conn)
JSONmessage = []byte(`{"Name":"Alice","Body":"Hello","Time":1294706395881547000}`)
writer.Write(JSONmessage)

And the server reads like this:

for {
    scanned := scanr.Scan()
    if !scanned {
      if err := scanr.Err(); err != nil {
        log.Println(err, conn.RemoteAddr())
        return err
      }
    }
    currentMessage := ParseJSON(scanr.Bytes())

The problem is that the server does not understand when the data transmitted by the client ends and waits until the client closes the connection or until the buffer overflows. In the case of strings, it was enough to pass the end-of-line character "\n", but what to do in the case of []byte is not clear.