Fix clippy::unused_async

.cargo/config.toml

@@ -8,7 +8,8 @@ clippy --workspace --no-deps -- \
   -D clippy::match-wildcard-for-single-variants \
   -D clippy::redundant-closure-for-method-calls \
   -D clippy::filter_map_next \
-  -D clippy::manual_let_else
+  -D clippy::manual_let_else \
+  -D clippy::unused_async
 """
 
 nitpick = """

examples/screenshot/Cargo.toml

@@ -7,7 +7,11 @@ publish = false
 
 [dependencies]
 iced.workspace = true
-iced.features = ["debug", "image", "advanced"]
+iced.features = ["debug", "image", "advanced", "tokio"]
+
+image.workspace = true
+image.features = ["png"]
+
+tokio.workspace = true
 
-image = { workspace = true, features = ["png"]}
 tracing-subscriber = "0.3"

examples/screenshot/src/main.rs

@@ -273,6 +273,8 @@ impl Application for Example {
 
 async fn save_to_png(screenshot: Screenshot) -> Result<String, PngError> {
     let path = "screenshot.png".to_string();
+
+    tokio::task::spawn_blocking(move || {
         img::save_buffer(
             &path,
             &screenshot.bytes,
@@ -282,6 +284,9 @@ async fn save_to_png(screenshot: Screenshot) -> Result<String, PngError> {
         )
         .map(|_| path)
         .map_err(|err| PngError(format!("{err:?}")))
+    })
+    .await
+    .expect("Blocking task to finish")
 }
 
 #[derive(Clone, Debug)]