Motivation:
Add support for HAProxyMessageEncoder.
This should help java based HAProxy server implementations propagate proxy information.
Modification:
Add public constructors for `HAProxyMessage`, `HAProxyTLV`, `HAProxySSLTLV`.
Add additional argument checks for `HAProxyMessage` and modify exceptions thrown when creating via public constructors directly.
Introduce a `@Sharable` `HAProxyMessageEncoder` which encodes a `HAProxyMessage` into a byte array.
Add an example `HAProxyServer` and `HAProxyClient` to `io.netty.example`
Result:
Fixes#10164
9ac005222b