✨ feat: 在src/instant.rs中添加JsInstant结构体及相关实现，在src/lib.rs中导出JsInstant

💡 docs: 在src/instant.rs中添加JsInstant的注释说明

Author: zhangzqs

src/instant.rs

@@ -33,8 +33,25 @@ impl InstantProvider<embassy_time::Duration> for embassy_time::Instant {
 }
 
 #[cfg(feature = "wasm")]
-impl InstantProvider<Duration> for js_sys::Date {
+/// A wrapper around `js_sys::Date` that implements `InstantProvider`.
+///
+/// This type stores the timestamp as milliseconds since the Unix epoch.
+#[derive(Clone, PartialEq)]
+pub struct JsInstant(f64);
+
+#[cfg(feature = "wasm")]
+impl Sub for JsInstant {
+    type Output = Duration;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        let delta_ms = self.0 - rhs.0;
+        Duration::from_millis(delta_ms as u64)
+    }
+}
+
+#[cfg(feature = "wasm")]
+impl InstantProvider<Duration> for JsInstant {
     fn now() -> Self {
-        js_sys::Date::new_0()
+        JsInstant(js_sys::Date::now())
     }
 }

src/lib.rs

@@ -8,6 +8,9 @@ pub use config::{ButtonConfig, Mode};
 pub use instant::InstantProvider;
 pub use pin_wrapper::PinWrapper;
 
+#[cfg(feature = "wasm")]
+pub use instant::JsInstant;
+
 /// Button configuration.
 pub mod config;
 /// Different current global time sources.