Simplify BTreeMap RangeSet min/max getters for Rust 1.66

quinn-proto/src/range_set/btree_range_set.rs

@@ -177,10 +177,11 @@ impl RangeSet {
     }
 
     pub fn min(&self) -> Option<u64> {
-        self.iter().next().map(|x| x.start)
+        self.0.first_key_value().map(|(&start, _)| start)
     }
+
     pub fn max(&self) -> Option<u64> {
-        self.iter().next_back().map(|x| x.end - 1)
+        self.0.last_key_value().map(|(_, &end)| end - 1)
     }
 
     pub fn len(&self) -> usize {

quinn-proto/src/range_set/tests.rs

@@ -149,6 +149,16 @@ macro_rules! common_set_tests {
                 }
             }
 
+            #[test]
+            fn min_max() {
+                let mut set = $set_type::new();
+                set.insert(1..3);
+                set.insert(4..5);
+                set.insert(6..10);
+                assert_eq!(set.min(), Some(1));
+                assert_eq!(set.max(), Some(9));
+            }
+
             fn create_initial_sets(max_range: u64) -> ($set_type, RefRangeSet) {
                 let mut set = $set_type::new();
                 let mut reference = RefRangeSet::new(max_range as usize);