[#3] dialer: Add default dialer.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

default.go

@@ -0,0 +1,31 @@
+package multinet
+
+import (
+	"context"
+	"fmt"
+	"net"
+)
+
+var (
+	defaultDialer    Multidialer
+	defaultDialerErr error
+)
+
+func init() {
+	var err error
+	defaultDialer, err = NewDialer(Config{
+		Balancer: BalancerTypeRoundRobin,
+		Subnets:  []string{"0.0.0.0/0", "::/0"},
+	})
+	if err != nil {
+		defaultDialerErr = fmt.Errorf("failed to initialize default dialier: %w", err)
+	}
+}
+
+// Dial dials provided network and address using default dialer.
+func Dial(network, address string) (net.Conn, error) {
+	if defaultDialerErr != nil {
+		return nil, defaultDialerErr
+	}
+	return defaultDialer.DialContext(context.Background(), network, address)
+}

default_test.go

@@ -0,0 +1,29 @@
+//go:build integration
+
+package multinet
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestDefaultDialer(t *testing.T) {
+	srv := startHTTP(t)
+	defer require.NoError(t, srv.Close())
+
+	conn, err := Dial("tcp", "localhost:8080")
+	require.NoError(t, err)
+	require.NoError(t, conn.Close())
+}
+
+func startHTTP(t *testing.T) *http.Server {
+	srv := &http.Server{Addr: ":8080"}
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { fmt.Fprintf(w, "Test stub") })
+	go func() {
+		require.ErrorIs(t, srv.ListenAndServe(), http.ErrServerClosed)
+	}()
+	return srv
+}