fix: Try to minimize frame latency

gst/src/plugins/app/appsink.rs

@@ -111,12 +111,20 @@ impl From<gstreamer::Sample> for Sample {
 }
 
 #[repr(transparent)]
+#[derive(Debug, Clone)]
 pub struct Sample {
-    inner: gstreamer::Sample,
+    pub inner: gstreamer::Sample,
 }
 
 use gstreamer::BufferRef;
 impl Sample {
+    #[doc(alias = "empty")]
+    pub fn new() -> Self {
+        Self {
+            inner: gstreamer::Sample::builder().build(),
+        }
+    }
+
     pub fn buffer(&self) -> Option<&BufferRef> {
         self.inner.buffer()
     }
@@ -124,6 +132,14 @@ impl Sample {
     pub fn caps(&self) -> Option<&gstreamer::CapsRef> {
         self.inner.caps()
     }
+
+    pub fn info(&self) -> Option<&gstreamer::StructureRef> {
+        self.inner.info()
+    }
+
+    // pub fn set_buffer(&mut self) {
+    //     self.inner.set_buffer(None);
+    // }
 }
 
 #[test]