feat!: make len/len_proxy consistent with Offsets

src/offset.rs

@@ -377,12 +377,18 @@ impl<O: Offset> OffsetsBuffer<O> {
         &self.0
     }
 
-    /// Returns the length of this container
+    /// Returns the length an array with these offsets would be.
     #[inline]
-    pub fn len(&self) -> usize {
+    pub fn len_proxy(&self) -> usize {
         self.0.len() - 1
     }
 
+    #[inline]
+    /// Returns the number of offsets in this container.
+    pub fn len(&self) -> usize {
+        self.0.len()
+    }
+
     /// Returns the byte slice stored in this buffer
     #[inline]
     pub fn as_slice(&self) -> &[O] {