Lay out device/stack interfaces - Netdev/Netlink (#92)

* good code today

* add netdev.Runner

* round off APIs more

* better interface method documentation

* improve DHCP netstack API

* add pico w netdev example

* remove temp file

* keep thinking about this. this is hard :/

* fix ci

* small fixer

* working dhcp

* fix rebase API mismatches

* begin adding espradio example

* keep working on espradio, icmp not working

* fix icmp by fixing dhcp

x/netdev/gonet.go

@@ -0,0 +1,30 @@
+package netdev
+
+import (
+	"net/netip"
+	"time"
+)
+
+// GoNet is the networking interface expected by TinyGo compiler/standard library.
+// The methods below define a networking stack as expected by the Go standard library
+// when using the TinyGo compiler+stdlib.
+type GoNet interface {
+	// GetHostByName returns the IP address of either a hostname or IPv4
+	// address in standard dot notation
+	GetHostByName(name string) (netip.Addr, error)
+
+	// Addr returns IP address assigned to the interface, either by
+	// DHCP or statically
+	Addr() (netip.Addr, error)
+
+	// Berkely Sockets-like interface, Go-ified.  See man page for socket(2), etc.
+	Socket(domain int, stype int, protocol int) (int, error)
+	Bind(sockfd int, ip netip.AddrPort) error
+	Connect(sockfd int, host string, ip netip.AddrPort) error
+	Listen(sockfd int, backlog int) error
+	Accept(sockfd int) (int, netip.AddrPort, error)
+	Send(sockfd int, buf []byte, flags int, deadline time.Time) (int, error)
+	Recv(sockfd int, buf []byte, flags int, deadline time.Time) (int, error)
+	Close(sockfd int) error
+	SetSockOpt(sockfd int, level int, opt int, value any) error
+}