Add Socket::open() to asynchronously connect

[thekid]

Use select() and test with isConnected() whether a connection has been established after calling this.

use peer\Socket;

$s= new Socket($host, $port);
$s->open();

$read= $write= $error= [$s];
$s->kind()->select($read, $write, $error);

$check= $s->isConnected();

• peer.Socket
• peer.BSDSocket

See https://gist.github.com/thekid/0b20593c563fea11def89f861aa2000f