by golangwink:

for {
        var e error
        frag, e = b.ReadSlice(delim)
        if e == nil { // got final fragment
            break
        }
        if e != ErrBufferFull { // unexpected error
            err = e
            break
        }

        // Make a copy of the buffer.
        buf := make([]byte, len(frag))
        copy(buf, frag)
        full = append(full, buf) // if full is too big?
    }

The bufio.ReadBytes don't have a limit to append, it isn't a problem when use if for
files, but when you use bufio.ReadBytes for net socket, the client may never give you
the correct delimiter.

Then the memory of server will use up by even if only a connection.

thank you for your attention!