Add progress on state_processing fixed-len update

eth2/utils/fixed_len_vec/src/lib.rs

@@ -17,6 +17,16 @@ where
     _phantom: PhantomData<N>,
 }
 
+impl<T, N: Unsigned> FixedLenVec<T, N> {
+    pub fn len(&self) -> usize {
+        self.vec.len()
+    }
+
+    pub fn capacity() -> usize {
+        N::to_usize()
+    }
+}
+
 impl<T: Default, N: Unsigned> From<Vec<T>> for FixedLenVec<T, N> {
     fn from(mut vec: Vec<T>) -> Self {
         dbg!(Self::capacity());
@@ -44,12 +54,6 @@ impl<T, N: Unsigned> Default for FixedLenVec<T, N> {
     }
 }
 
-impl<T, N: Unsigned> FixedLenVec<T, N> {
-    pub fn capacity() -> usize {
-        N::to_usize()
-    }
-}
-
 impl<T, N: Unsigned, I: SliceIndex<[T]>> Index<I> for FixedLenVec<T, N> {
     type Output = I::Output;