Proxy protocol parser kept sub-slice reference for pooled bytesBuffer at readProxyProto
```
bb := bbPool.Get()
defer bbPool.Put(bb) // ← buffer returned to pool AFTER function returns
...
IP: bb.B[0:16], // ← BUG: sub-slice of pooled buffer!
...
```
This commit properly allocates new slice for ipv6 address and copies buffer content to it.
Fixes https://github.com/VictoriaMetrics/VictoriaMetrics/issues/10839
Previously, tcp listener perform synchronous proxy protocol header
read during connection accept. It could significantly reduce vmauth
performance and lead to timeout at serving http requests.
This commit changes this logic and performs proxy protocol header
parsing during first Read request from connection or RemoteAddr method
call. It significantly improves performance and reduce possible
bottleneck at connections accept method.
Related PR https://github.com/VictoriaMetrics/VictoriaMetrics/pull/9546/
