Add API docs. Do small refactors

v3/pkg/application/mainthread.go

@@ -19,3 +19,57 @@ func generateFunctionStoreID() uint {
 		}
 	}
 }
+
+func InvokeSync(fn func()) {
+	var wg sync.WaitGroup
+	wg.Add(1)
+	globalApplication.dispatchOnMainThread(func() {
+		defer processPanicHandlerRecover()
+		fn()
+		wg.Done()
+	})
+	wg.Wait()
+}
+
+func InvokeSyncWithResult[T any](fn func() T) (res T) {
+	var wg sync.WaitGroup
+	wg.Add(1)
+	globalApplication.dispatchOnMainThread(func() {
+		defer processPanicHandlerRecover()
+		res = fn()
+		wg.Done()
+	})
+	wg.Wait()
+	return res
+}
+
+func InvokeSyncWithError(fn func() error) (err error) {
+	var wg sync.WaitGroup
+	wg.Add(1)
+	globalApplication.dispatchOnMainThread(func() {
+		defer processPanicHandlerRecover()
+		err = fn()
+		wg.Done()
+	})
+	wg.Wait()
+	return
+}
+
+func InvokeSyncWithResultAndError[T any](fn func() (T, error)) (res T, err error) {
+	var wg sync.WaitGroup
+	wg.Add(1)
+	globalApplication.dispatchOnMainThread(func() {
+		defer processPanicHandlerRecover()
+		res, err = fn()
+		wg.Done()
+	})
+	wg.Wait()
+	return res, err
+}
+
+func InvokeAsync(fn func()) {
+	globalApplication.dispatchOnMainThread(func() {
+		defer processPanicHandlerRecover()
+		fn()
+	})
+}