made clippy quiet

src/any/performance/gradual.rs

@@ -168,6 +168,7 @@ impl GradualPerformance {
     }
 
     /// Returns the amount of remaining objects.
+    #[allow(clippy::len_without_is_empty)]
     pub fn len(&self) -> usize {
         match self {
             GradualPerformance::Osu(gradual) => gradual.len(),