net: extract a common Socket struct, reuse it by embedding in TcpSocket & UdpSocket (#13559)

vlib/net/socket.v

@@ -0,0 +1,11 @@
+module net
+
+pub struct Socket {
+	pub:
+	handle int
+}
+
+// address gets the address of a socket
+pub fn (s &Socket) address() ?Addr {
+	return addr_from_socket_handle(s.handle)
+}

vlib/net/tcp.v

@@ -296,8 +296,7 @@ pub fn (c &TcpListener) addr() ?Addr {
 }
 
 struct TcpSocket {
-pub:
-	handle int
+	Socket
 }
 
 fn new_tcp_socket(family AddrFamily) ?TcpSocket {
@@ -418,8 +417,3 @@ fn (mut s TcpSocket) connect(a Addr) ? {
 	// otherwise we timed out
 	return err_connect_timed_out
 }
-
-// address gets the address of a socket
-pub fn (s &TcpSocket) address() ?Addr {
-	return addr_from_socket_handle(s.handle)
-}

vlib/net/udp.v

@@ -8,8 +8,8 @@ const (
 )
 
 struct UdpSocket {
-	handle int
-	l      Addr
+	Socket
+	l Addr
 	// TODO(emily): replace with option again
 	// when i figure out how to coerce it properly
 mut:
@@ -259,11 +259,6 @@ fn new_udp_socket_for_remote(raddr Addr) ?&UdpSocket {
 	return sock
 }
 
-// address gets the address of a socket
-pub fn (s &UdpSocket) address() ?Addr {
-	return addr_from_socket_handle(s.handle)
-}
-
 pub fn (mut s UdpSocket) set_option_bool(opt SocketOption, value bool) ? {
 	// TODO reenable when this `in` operation works again
 	// if opt !in opts_can_set {