refactor(tracker): change so that all icon initialization is a lazy & cache in iconcache

tracker/iconcache.go

@@ -0,0 +1,22 @@
+package tracker
+
+import (
+	"log"
+
+	"gioui.org/widget"
+)
+
+var iconCache = map[*byte]*widget.Icon{}
+
+// widgetForIcon returns a widget for IconVG data, but caching the results
+func widgetForIcon(icon []byte) *widget.Icon {
+	if widget, ok := iconCache[&icon[0]]; ok {
+		return widget
+	}
+	widget, err := widget.NewIcon(icon)
+	if err != nil {
+		log.Fatal(err)
+	}
+	iconCache[&icon[0]] = widget
+	return widget
+}