HevBuffer: Init.
HevSocks5Proto: Return unpack left size.
HevDNSResolver: Track current buffer.
HevSocks5Proto: Return 0 directly if atype not supported.
HevSocks5Proto: Add replies.
HevSocks5Proto: Update addr and port packing.
HevSocket: Init.
HevSocks5Session: Handle socks5 protocol.