RefIter: add len/is_empty methods

Cargo.toml

@@ -2,7 +2,7 @@
 name = "varstack"
 description = "A call-stack based singly-linked list"
 repository = "https://git.exozy.me/fogti/varstack.git"
-version = "0.2.3"
+version = "0.2.4"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 

src/ref.rs

@@ -82,7 +82,7 @@ impl<'s, V> RefStack<'s, V> {
         false
     }
 
-    #[inline]
+    #[inline(always)]
     pub fn len(&self) -> usize {
         self.iter().count()
     }
@@ -105,6 +105,18 @@ impl<'s, V> IntoIterator for &'s RefStack<'s, V> {
 
 pub struct RefIter<'s, V>(pub Option<&'s RefStack<'s, V>>);
 
+impl<'s, V> RefIter<'s, V> {
+    #[inline(always)]
+    pub fn is_empty(&self) -> bool {
+        self.0.is_none()
+    }
+
+    #[inline(always)]
+    pub fn len(&self) -> usize {
+        self.count()
+    }
+}
+
 impl<V> marker::Copy for RefIter<'_, V> {}
 
 impl<V> clone::Clone for RefIter<'_, V> {