add custom transform example and remove calls to deprecated methods

examples/plugins/basetransform/main.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/signal"
+
+	"github.com/go-gst/go-gst/examples/plugins/basetransform/internal/customtransform"
+	"github.com/go-gst/go-gst/gst"
+)
+
+func run(ctx context.Context) error {
+	ctx, cancel := signal.NotifyContext(ctx, os.Interrupt)
+	defer cancel()
+
+	gst.Init(nil)
+
+	customtransform.Register()
+
+	pipeline, err := gst.NewPipelineFromString("audiotestsrc ! gocustomtransform ! fakesink")
+
+	if err != nil {
+		return err
+	}
+
+	pipeline.SetState(gst.StatePlaying)
+
+	<-ctx.Done()
+
+	pipeline.BlockSetState(gst.StateNull)
+
+	gst.Deinit()
+
+	return ctx.Err()
+}
+
+func main() {
+	ctx := context.Background()
+
+	err := run(ctx)
+
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+	}
+}